The production cost of a single unit of a manufactured product is determined by: a. dividing total direct materials and direct labor for a production run by the number of units made. b. dividing total direct materials, direct labor, and manufacturing overhead for a production run by the number of units made. c. dividing total direct materials, direct labor, manufacturing overhead and selling expenses for a production run by the number of units made. d. dividing the selling price by the gross profit ratio