Availability of a System Refers to the ______

Availability of a system refers to the ______.

A) percentage of the time that a system is operating properly when it is needed for use
B) percentage of the time that a system is down for maintenance
C) percentage of components in the system that have a backup component
D) percentage of the time that a system is available for use by the department that owns it (and is not being used by other departments)