Problem: Indicate whether each of the following costs is a product cost or a period cost. Assume it is for a manufacturer. A. direct materials used in factory Product cost B. factory utilities Product cost C. sales persons' commissions Period cost D. salary of plant manager Product cost E. indirect materials used in factory Product cost F. depreciation expense on store equipment Period cost G. indirect labor incurred in factory Product cost H. advertising expense Period cost I. direct labor incurred in factory Product cost J. factory machinery repairs and maintenance Product cost K. depreciation expense on factory machinery Product cost L. supplies used in store Period cost M. plant insurance expired Product cost