Estimated manufacturing overhead Estimated machine hours Actual machine hours worked information: $690,000 46,000 60,000 Actual costs incurred: Indirect materials Indirect labor Utilities Insurance Rent $170,000 230,000 110,000 100,000 80,000 Assuming that overhead is applied based on an overhead rate calculated using machine hours as the base in the highly automated production environment, the amount o or underapplied overhead is Oa. $210,000 underapplied. Ob. $50,000 overapplied. Oc. $50,000 underapplied. Od. $210,000 overapplied