Which of the following statements is correct?

A. Product costs for a merchandiser are expensed as selling, general, and administrative expensed when the related unit is sold.

B. Period costs are relevant for purposes of calculating Gross Profit on the Income Statement for a both a merchandiser and a manufacturer.

C. Product costs for a manufacturer are categorized as either direct material, direct labor, or manufacturing overhead costs.

D. All links in the value chain applicable to a service company are considered product costs.

E. More than one of the above statements is correct.