Which of the following counters is used to measure the time the processor is busy executing a non-idle thread?

A.
Percent of User Time

B.
Percent Processor Time

C.
Percent of Interrupt Time

D.
Interrupts Per Second

E.
Percent of Privileged Time

F.
Percent Total Processor Time

Explanation:
Percent Processor Time measures the period that a processor is busy executing a non-idle thread. Idle threads are assigned to each processor to consume non-productive clock cycles.
Incorrect
Answers:

A: Percent of User Time measures the processor time spent in User Mode executing non-idle threads.
C: Percent of Interrupt Time measures the percentage of elapsed time that the processor spends handling hardware interrupts.
D: Interrupts Per Second measures the number of device interrupts the processor is currently experiencing.
E: Percent of Privileged Time measures the percentage of processor time spent in Privileged Mode executing non-idle threads.
F: Percent Total Processor Time measures the multiprocessor systems only, this counter is used the same way as that for a single CPU counter.
References:
Charles J. Brooks, Server+ Certification Exam Cram 2 (Exam SK0-002), QUE Publishing, Indianapolis, 2006, pp. 335, 336