Before adding adapter cards, for which combination of elements should you verify compatibility?

A.
Server board, associated adapter slot.

B.
Server board and all other cards installed in the server.

C.
All cards installed in the server.

D.
Server board, associated adapter slot, and all other cards installed in the server.

Explanation:
Before attempting to install any additional adapter cards, you need to verify compatibility between the server board, associated adapter slot, and all other cards already installed in the server. This applies for adapter upgrades involving NICs, SCSI cards and RAID controllers.
References:
Charles J. Brooks, Server+ Certification Exam Cram 2 (Exam SK0-002), QUE Publishing, Indianapolis, 2006, pp. 405-406.