Which of the following statements is correct? A. All links in the value chain applicable to a service company are considered period costs. B. Product costs for a merchandiser are categorized as either direct material, direct labor, or manufacturing overhead costs. C. Period costs are relevant for purposes of calculating Gross Profit on the Income Statement for a both a merchandiser and a manufacturer. D. Product costs for a merchandiser are expensed as selling, general, and administrative expensed when the related unit is sold. E. Costs incurred in the production link in the value chain for a manufacturer are expensed when incurred