Which of the following is usually measured in nanoseconds?

A.
Switching transient

B.
Over-voltage

C.
Under-voltage

D.
None of the above

Explanation:
A switching transient is a very brief under-voltage, shorter than a spike, and generally measured in nanoseconds.

References:
Charles J. Brooks, Server+ Certification Exam Cram 2 (Exam SK0-002), QUE Publishing, Indianapolis, 2006, pp. 227-240.