Blue Ridge Marketing Inc. manufactures two products, A and B. Presently, the company uses a single plantwide factory overhead rate for allocating overhead to products. However, management is considering moving to a multiple department rate system for allocating overhead. The following table presents information about estimated overhead and direct labor hours. Using a single plantwide rate, the factory overhead allocated per unit of Product B is a. $640 b. $496 c. $320 d. $144