Final answer:
Sheet steel in a file cabinet made by the company should not be included as part of manufacturing overhead because it is a direct material cost, not an indirect cost like manufacturing equipment depreciation or factory building taxes. The correct option is A.
Step-by-step explanation:
The question focuses on identifying which cost should not be included as part of manufacturing overhead in a company that makes office furniture. Manufacturing overhead typically includes all costs associated with the production process that are not directly tied to the creation of the product. These costs might include the depreciation of manufacturing equipment, taxes on the factory building, and wages paid during idle time for direct labor.
However, materials used in production, such as sheet steel in a file cabinet, are classified as direct materials rather than manufacturing overhead. Thus, sheet steel in a file cabinet is the cost that should not be included in manufacturing overhead, as it is a direct material cost.