The Computer Hut manufactured 100 personal computers at a cost of $60,000. It can either sell them as is for $90,000 or install new hard disks in them at an additional cost of $25,000 and then sell them for $130,000. The $60,000 original manufacturing cost is:

A. An out-of-pocket cost because it has already been paid.
B. A sunk cost because it is relevant to the decision.
C. An incremental cost because it is relevant to the decision.
D. A fixed cost because it will remain the same no matter which action is taken.