A server that is crucial for daily operations is experiencing degraded performance.

The correct answer is D. Replace the drive with a cold-swappable drive .

According to CompTIA A+ Core 1 220-1201 objectives under Storage and RAID:

RAID 5 provides both data striping and parity for fault tolerance, but if the RAID controller does not support hot swapping, replacing a failed drive while the system is running is not possible.

Cold-swappable drives are designed to be safely removed and replaced when the system is powered down, which allows maintenance without damaging the array or system.

Why the other options are incorrect:

A. Update the RAID controller firmware to support hot swapping: Firmware updates may add hot swap functionality, but this is not guaranteed and may require a system reboot.

B. Implement a software-based RAID solution: Software RAID requires a system reconfiguration and downtime; it does not immediately resolve the degraded RAID 5 array.

C. Change the drive during off-peak hours: While feasible, this is essentially the same as using a cold-swappable drive but is less precise; using cold-swappable drives ensures safe replacement without downtime considerations.