Which of the following provides fault tolerance in a RAID-5 implementation?

A.
duplexing

B.
mirroring

C.
striping

D.
parity

Explanation:
RAID-5 uses parity information to reconstruct missing data should a disk fail. Thus, parity provides fault tolerance.
Incorrect Answers:
A: Disk duplexing uses mirroring to write data to two disks so that the two are exact copies of one another but each drive is attached to its own disk controller..
B: Mirroring is the process of duplicating data to two disks. This provides fault tolerance.
However, mirroring is used in RAID-1; RAID-5 uses striping with parity.
C: Striping allows information to be stored in blocks across multiple disks and improves read/write performance. It does not provide fault tolerance.
References:
Charles J. Brooks, Server+ Certification Exam Cram 2 (Exam SK0-002), QUE Publishing, Indianapolis, 2006, pp. 184-192.
David Groth and Toby Skandier, Network+ Study Guide (4th Edition), Sybex, Alameda CA, 2005, pp. 381-382.