Which of the Following Statements Regarding Short-Term Decisions Is True

Which of the following statements regarding short-term decisions is true?

A) Fixed costs must only be considered on a per unit basis.
B) Fixed costs will actually behave as variable costs when they are unitised for special decisions.
C) Unitised fixed costs are valid only for make or buy decisions.
D) Unitised fixed costs are misleading because they appear to behave as variable costs when in fact they are not.