A technician is working on a RAID 1 array that is apparently degraded.

Comprehensive and Detailed In-Depth Explanation:

A degraded RAID 1 array usually means one of the drives has failed or is failing. The correct next step is to run diagnostics on each drive to identify the faulty one. RAID 1 uses mirroring, so one good drive should still contain all the data.

Option B: chkdsk checks file system integrity, not hardware drive health.

Option C: Rebuilding should only occur after identifying and replacing a faulty drive.

Option D: RAID 0 offers no redundancy and would destroy data in this context.

CompTIA A+ Core 1 Exam Objective Reference:

Objective 3.5: Given a scenario, troubleshoot problems related to storage devices.