Rent on leased factory machinery is classified as c manufacturing overhead cost.
Explanation: Manufacturing overhead costs include all costs that are not directly associated with the production of a specific product but are necessary for the production process. This includes costs such as utilities, rent, and any depreciation on factory equipment. Since leased machinery rent does not fall under direct materials or direct labor, it is categorized as manufacturing overhead as it contributes to the overall production process but is not directly traceable to specific units of product made.