What does the Disk Bytes/sec displays?

A.
It measurement is the rate at which bytes are transferred to or from the disk during write or read operations.

B.
It displays the size of the virtual memory currently on the Zeroed, Free, and Standby lists.

C.
It displays is the number of pages read from or written to the disk to resolve memory references to pages that were not in memory at the time of the reference.

D.
None of the above.

Explanation:
The Disk Bytes/sec measures the rate at which bytes are transferred to or from the disk during write or read operations.
Incorrect Answers
B: The Available Bytes displays the size of the virtual memory currently on the Zeroed, Free, and Standby lists.
C: The Pages/sec displays the number of pages read from or written to the disk to resolve memory references to pages that were not in memory at the time of the reference.
References:
Charles J. Brooks, Server+ Certification Exam Cram 2 (Exam SK0-002), QUE Publishing, Indianapolis, 2006, p. 347