Final answer:
The salary of an assembly line supervisor is classified as Indirect labor because it is not directly attributable to the making of a single product but is instead spread across supervision of the production of multiple products. The correct option is B.
Step-by-step explanation:
The salary paid to the supervisor of an assembly line that produces more than one type of a product would normally be classified as Indirect labor. This is because the supervisor's work is not directly attributable to the manufacturing of one specific product but is spread over the supervision of the production of several different products. Direct labor refers to the wages of employees who actually manufacture the products, such as workers on the assembly line.
However, since supervisors oversee the process and do not directly engage in the hands-on work of creating products, their wages are considered part of the overhead and not directly tied to any single unit of production. Hence, they fall under the category of indirect costs.
The roles on assembly lines have evolved to be less skilled due to the mechanization and standardization of tasks, making most jobs boring and repetitious. Supervisors, on the other hand, hold a managerial role that transcends the direct production activities. Their compensation is often treated as a fixed cost within the cost accounting system of a company.
Hence, Option B is correct.