The correct answer is C. Cat 6.
An RJ45 connector is a standard type of physical connector for network cables. RJ45 connectors are used almost exclusively with Ethernet cables and networking1. Ethernet cables are twisted pair cables that carry data signals between devices on a network, such as computers, routers, switches, and servers2.
There are different categories of Ethernet cables, such as Cat 5, Cat 5e, Cat 6, and Cat 7, that have different specifications and performance levels. Cat 6 is one of the most common types of Ethernet cables, which supports data transfer speeds up to 10 Gbps and bandwidth up to 250 MHz3. Cat 6 cables have four pairs of copper wires, each with a plastic insulation and a foil or braided shield. The wires are twisted together to reduce crosstalk and interference4.
To terminate a Cat 6 cable, an administrator needs to use an RJ45 connector that matches the wiring scheme of the cable. There are two common wiring schemes for Ethernet cables: T568A and T568B. The administrator needs to strip the cable jacket, untwist the wires, arrange them in the correct order according to the chosen scheme, trim the excess wire, and insert them into the RJ45 connector. Then, the administrator needs to use a crimping tool to secure the wires and the connector4.
Optical cables are not terminated with RJ45 connectors, but with different types of connectors that can transmit light signals, such as SC, ST, LC, or MTRJ connectors. Optical cables are used for fiber-optic networks that can carry data over long distances at high speeds.
Serial cables are not terminated with RJ45 connectors, but with different types of connectors that can transmit serial data signals, such as DB9, DB25, or DE9 connectors. Serial cables are used for connecting devices that use serial communication protocols, such as modems, printers, scanners, or keyboards.
USB cables are not terminated with RJ45 connectors, but with different types of connectors that can transmit universal serial bus data signals, such as USB-A, USB-B, USB-C, or Micro-USB connectors. USB cables are used for connecting devices that use USB communication protocols, such as flash drives, cameras, mice, or chargers.

The Trusted Platform Module (TPM) is a hardware component that provides cryptographic functions and secure storage for encryption keys, passwords, and certificates. BitLocker requires a TPM to be enabled and activated in the BIOS or UEFI settings of the laptop in order to use SSD-level encryption. The technician should check that the TPM is enabled and activated before trying to turn on BitLocker. Reference:
https://partners.comptia.org/docs/default-source/resources/a-core-series-combined-content-guide (page 34)

Hyperthreading is a feature of some CPUs that allows them to execute two threads (sequences of instructions) simultaneously on each core. Hyperthreading can improve the performance of CPU-intensive tasks, such as data analytics, by increasing the utilization of CPU resources and reducing idle time. The technician should verify that hyperthreading is enabled in the BIOS settings of the workstation.

DNS servers are responsible for translating domain names into IP addresses, which are used to access websites. If the phone has limited internet connectivity, it might be because the DNS servers are not working properly or are blocked by the network. The technician should check the DNS settings on the phone and try to use a different DNS server, such as Google DNS (8.8.8.8 or 8.8.4.4) or Cloudflare DNS (1.1.1.1 or 1.0.0.1).
References
*9 Best Ways to Fix Wi-Fi Showing Limited Connectivity in Android
*7 Easy Ways to Fix Limited Wi-Fi Connectivity on Android
*How to Fix Limited Connectivity Issue in Android Wi-Fi

The correct answer is D. VPN.
A VPN (Virtual Private Network) is a service that allows a remote user to access network resources securely over the internet. A VPN creates an encrypted tunnel between the user's device and the VPN server, which acts as a gateway to the network. The user can then access the network resources as if they were directly connected to the network, without exposing their traffic to eavesdropping, interception, or censorship.
A VPN can provide remote users with access to various services on a company network, such as file and print services, client/server applications, and remote network administration1. A VPN can also protect the user's privacy and identity online by masking their IP address and location.
References:
*Remote Access to a Network - NETWORK ENCYCLOPEDIA, section "Remote access typically gives remote users access to the following services on a company network".