What’s the best way to handle a memory upgrade?

One of your end-users would like to upgrade the memory in their desktop computer. What’s the best way to proceed with the memory upgrade?

A) Use the existing memory as a guide for the upgrade.

B) Memory purchased from large electronic retailers will work in most computers.

C) The computer manufacturer’s documentation will have detailed memory upgrade specifications.

D) Online web searches are the best source for accurate information on PC memory upgrades.