A job order cost system uses a predetermined overhead rate based on estimated ac

A job order cost system uses a predetermined overhead rate based on estimated activity and estimated manufacturing overhead cost. At the end of the year underapplied overhead might be explained by which of the following situations?A)B)C)D)Actual activityActual manufacturing overhead costsGreater than estimatedGreater than estimatedGreater than estimatedLess than estimatedLess than estimatedGreater than estimatedLess than estimatedLess than estimatedThe correct answer is C.How to solve this kind of problem?And I am confused why A is wrong. Suppose the estimated cost is 100 and estimated labor hour is 50 so the predetermined overhead rate is 2. In choice A the actual activity is greater than estimated (suppose it is 60) and the actual overhead costs are grater than estimated (suppose it is 150). Because the predetermined overhead rate is 2 so overhead applied is 120. 120 is less than 150 so isnt A correct? I am very confused.