Which statement about parity-based RAID levels is true?

• A. They use parity to provide redundancy.
• B. They do not use parity at all.
• C. Parity data is stored on a single disk only.
• D. They cannot be rebuilt after a disk failure.

Answer: (A)

Parity-based RAID levels store parity information to provide redundancy and enable recovery if a disk fails. Parity isn’t confined to one disk; it’s distributed across the drives (parity rotates in levels like RAID 5, and RAID 6 adds a second parity). This distributed parity lets the array reconstruct the missing data on a replacement disk using the surviving data and parity. That capability is exactly why these levels can tolerate failures and be rebuilt. So the statement that they use parity is true, while saying they don’t use parity, that parity is stored on a single disk, or that they cannot be rebuilt after a failure would all be incorrect.