A cabinet factory pays wages to production workers who build wooden shelves for use inside the factory. How is that wage cost classified?

1. Direct labor is the cost of hourly wages of production workers who assemble goods that customers buy. 2. The shelves stay in the factory, so this labor never becomes part of a product sold to a customer. 3. Factory overhead covers any expense in a factory that cannot be traced to products customers purchase, including wages of factory workers who assemble shelves. 4. Selling and administrative expenses arise outside the factory production area, so neither fits work done on the factory floor. 5. The wages are therefore factory overhead. _Source: Jonick, Principles of Managerial Accounting (UNG Press, CC BY-SA 4.0), section 1.2 Cost Terminology and Concepts_