Which of the following RAID levels supports fault tolerance by writing parity to only one drive in the array?

In RAID 3, all parity information is written exclusively to one dedicated parity drive, while data is striped at the byte level across the remaining drives in the array. Any single data drive failure can be recovered by XORing the surviving data drives with the contents of that dedicated parity drive. This single-dedicated-parity-drive design is what explicitly distinguishes RAID 3 from RAID 5, where parity is distributed across all drives.

RAID 5 distributes parity data in blocks across all drives in the array rather than confining parity to a single dedicated drive, making it a distributed-parity configuration.

RAID 6 writes dual parity across two different drives to tolerate two simultaneous drive failures, which does not match the single-parity-drive description in the question.

RAID 10 combines mirroring and striping for redundancy but uses no parity at all - fault tolerance is achieved through full data mirroring, not parity calculation.