High availability can be provided by ______. (Choose all that apply)

A.
clustering

B.
fault tolerance

C.
scaling up

D.
scaling out

Explanation:
High availability is the ability of a server system to remain functioning despite a software or hardware failure. This can be accomplished through scaling out, clustering and fault tolerance.
Incorrect Answers:
C: Scaling up provides improved server performance but does not provide high availability.
References:
Charles J. Brooks, Server+ Certification Exam Cram 2 (Exam SK0-002), QUE Publishing, Indianapolis, 2006, pp. 40-54.