Which one of the following describes a covert timing channel?

A.
Modulated to carry an unintended information signal that can only be detected by special,
sensitive receivers.

B.
Used by a supervisor to monitor the productivity of a user without their knowledge.

C.
Provides the timing trigger to activate a malicious program disguised as a legitimate function.

D.
Allows one process to signal information to another by modulating its own use of system
resources.

Explanation:
A covert channel in which one process signals information to another by modulating
its own use of system resources (for example, CPU time) in such a way that this manipulation
affects the real response time observed by the second process. – Shon Harris All-in-one CISSP
Certification Guide pg 929