The answer is D. Perform a full backup.
Before replacing a failed drive in a RAID 5 array, the technician should perform a full backup of the data on the array to ensure that no data is lost during the hot swapping process. Hot swapping is the process of replacing a drive without shutting down the system or the array, which allows for faster recovery and minimal downtime. However, hot swapping also involves some risks, such as accidentally removing the wrong drive, damaging the new drive, or encountering another drive failure during the rebuild process. Therefore, performing a full backup is a precautionary measure that can prevent data loss in case of any unexpected errors or complications.
The other options are not the first steps that the technician should take before hot swapping the drive. Documenting the replacement date is a good practice, but it is not as important as backing up the dat a) Shutting down the array is not necessary for hot swapping, and it may cause more disruption to the system or the users. Safely disposing of the failed drive is a step that should be done after replacing it, not before.
Reference:
Hot-swapping the hard drives when the RAID crashes | QNAP, section "Install a new drive to rebuild RAID 5 by hot swapping": "Important: Do not install a new drive when the system is not in degraded mode, otherwise you may encounter unexpected system failures." Hot Swapping hard drives on Raid 5 with data on them - Spiceworks Community, reply by Magnus369: "Part of that slowness would be the raid level you are using. Highly doubt you can change it without losing data either, but your writes are going to be atrociously slow due to having to figure out parity across 11 drives for each write you do. While you may have a ton of space, it's unstable and subject to self destruction." hard drive - How do I Change a damaged Disk in a Raid 5 array - Server Fault, answer by Chris S: "If you have another disk failure during rebuild you will lose all your data."

Switches only send data to the specific computer, while hubs send data to all computers inside the network. Reference: CompTIA A+ Certification Exam Guide, Exam 220-1001, Page 323

A router is a device that can dynamically distribute an IP address to the devices connected to its network using a protocol called DHCP (Dynamic Host Configuration Protocol). DHCP allows a router to automatically assign an IP address and other network configuration information to a device when it joins the network, without requiring manual intervention from the administrator. A router can also act as a gateway between different networks, such as a local area network (LAN) and the internet1.
A hub is a device that connects multiple devices on a network and forwards data packets between them. However, a hub does not assign IP addresses or perform any routing functions. A hub operates at the physical layer of the OSI model and does not understand IP addresses or other network protocols.
A switch is a device that connects multiple devices on a network and forwards data packets between them based on their MAC addresses. A switch can improve the performance and security of a network by reducing collisions and isolating traffic. However, a switch does not assign IP addresses or perform any routing functions. A switch operates at the data link layer of the OSI model and does not understand IP addresses or other network protocols.
An injector is a device that provides power to another device over an Ethernet cable, such as a wireless access point or a security camera. This is also known as Power over Ethernet (PoE). An injector does not assign IP addresses or perform any routing functions. An injector operates at the physical layer of the OSI model and does not understand IP addresses or other network protocols.

The most likely cause of the issue is that the page orientation is incorrect. The printer may be set to print labels in a different orientation than the orientation of the label sheet1.

Using the device as a Wi-Fi hotspot, a failing battery, and too many open applications are the most likely causes of the cell phone getting hot. These actions require the phone to use more power and processing, causing it to heat up.