Which of the following statements is true for a firm that uses variable costing? A. The cost of a unit of product changes because of changes in number of units manufactured. B. Profits fluctuate with...

Which of the following statements is true for a firm that uses variable costing?

A. The cost of a unit of product changes because of changes in number of units manufactured.
B. Profits fluctuate with sales.
C. An idle facility variation is calculated.
D. Product costs include variable administrative costs.