Which of the Following Statements Concerning Variable Costs Is (Are)

Multiple Choice

Which of the following statements concerning variable costs is (are) correct?
I. Variable costs minus fixed costs equal marginal costs.
II. Variable costs are equal to zero when production is equal to zero.
III. An increase in variable costs increases the operating cash flow.

A) II only
B) III only
C) I and III only
D) II and III only
E) I and II only