The best tool to identify the correct cable is C. Toner probe.
A toner probe is a device that can be used to locate and trace a specific cable within a network rack or a wall outlet. A toner probe consists of two parts: a tone generator and a tone detector. The tone generator is connected to one end of the cable and sends an audible signal through the cable. The tone detector is used to scan the other end of the cable and pick up the signal. The tone detector emits a sound or a light when it detects the signal, indicating the correct cable.
A toner probe can be useful for network technicians who need to locate an end user's Cat 6 cable within a network rack that is poorly documented and has no cable management system. A Cat 6 cable is a type of twisted pair cable that can support high-speed data transmission over Ethernet networks. A network rack is a frame that holds network equipment, such as servers, switches, routers, or patch panels. A cable management system is a set of devices or methods that organize and secure the cables within a network rack .
The other options are not the best tools to identify the correct cable, because they have different purposes or limitations. A cable tester (option A) is a device that can be used to test the functionality and quality of a cable, such as its continuity, resistance, or interference. A cable tester can help diagnose and troubleshoot faulty cables, but it cannot locate or trace specific cables within a network rack. A network tap (option B) is a device that can be used to monitor and analyze the traffic and data that pass through a network. A network tap can help capture and inspect network packets, but it cannot locate or trace specific cables within a network rack. A loopback plug (option D) is a device that can be used to test the functionality and connectivity of a port or an interface. A loopback plug can help verify if a port or an interface is working properly, but it cannot locate or trace specific cables within a network rack.
For more information about toner probes and other network tools, you can refer to the following web search results: [What Is a Toner Probe?], [What Is Cat 6 Cable?], [What Is a Network Rack?], [What Is a Cable Tester?], [What Is a Network Tap?], [What Is a Loopback Plug?].

When a new GPU is installed and results in lower screen resolution and picture quality, it's often because the appropriate OEM (Original Equipment Manufacturer) drivers for the GPU have not been installed. Without these drivers, the operating system may revert to generic drivers that do not fully support the GPU's capabilities, leading to suboptimal performance. Installing the correct OEM drivers should resolve the issue and allow the GPU to function at its intended performance level.
References:
* CompTIA A+ Core 1 (220-1101) Exam Objectives, particularly those relating to the installation and configuration of hardware components like GPUs, and the importance of installing the correct device drivers for optimal hardware performance.
* General knowledge of hardware installation and the role of device drivers in ensuring hardware components such as GPUs operate correctly within a system.

GPS (Global Positioning System) is a feature that allows a phone to determine its location by receiving signals from satellites. A maps application relies on GPS to provide accurate directions and navigation. If GPS is turned off or not working properly, the maps application may not function as expected.
The other options are not relevant to the issue. Airplane mode is a setting that disables all wireless communication on a phone, including cellular, Wi-Fi, Bluetooth, and GPS. However, since the representative runs a speed test and gets ~10Mbps in both directions, it means that airplane mode is not enabled. PRL (Preferred Roaming List) is a database that contains information about the cellular towers and networks that a phone can connect to. Updating the PRL can improve the phone's signal strength and coverage, but it does not affect the maps application. LTE (Long Term Evolution) is a standard for high-speed wireless communication on mobile devices. It is related to the cellular data speed and quality, but not to the maps application.
To troubleshoot the issue, the technician should check the GPS settings on the phone and make sure that it is turned on and has a clear view of the sky. The technician should also verify that the maps application has permission to access the GPS location. If the problem persists, the technician may suggest resetting the network settings, updating the phone's software, or contacting the maps application's support team.
References:
* CompTIA A+ Certification Exam Core 1 Objectives1
* The Official CompTIA A+ Core 1 Student Guide (Exam 220-1101) eBook2
* How to Fix Google Maps When It's Not Working on Android - MUO3
* Apple Maps Not Working? 5 Fixes to Get You Back on the Road (2023)4

When replacing a power supply in a computer, wearing an antistatic wrist strap is crucial to prevent static electricity from damaging the computer components. Static electricity can easily damage sensitive electronic components within the computer; therefore, using an antistatic wrist strap helps to ground the technician, mitigating the risk of electrostatic discharge. The other options provide general safety but do not address the primary concern of electrostatic discharge in this context.
References:CompTIA A+ Core 1 (220-1101) objectives covering best practices for hardware maintenance, including electrostatic discharge prevention.

The fuser is the part of a laser printer that uses heat and pressure to fuse the toner to the paper. If the fuser is defective or not hot enough, the toner may not adhere properly and smear when touched. The duplexing assembly, toner, and transfer belt are not related to this issue.
Reference: Official CompTIA learning resources CompTIA A+ Core 1 and Core 2, page 11.