Which of the following is an Under-voltage condition?

A.
Spikes and surges

B.
Power sags

C.
Brownouts

D.
None of the above.

Explanation:
A brownout is a reduction in line voltage for an extended time period, ranging from a few minutes to a few days. Under-voltages are responsible for malfunctions and

unexpected shutdowns of computer and process control equipment.
References:
Charles J. Brooks, Server+ Certification Exam Cram 2 (Exam SK0-002), QUE Publishing, Indianapolis, 2006, pp. 227-240.