All the following statements about predetermined overhead rates are correct, EXCEPT: O a. All the given answers are correct. O b. calculated first and then multiplied by total actual units of the allocation base to compute the applied manufacturing overhead costs. O c. calculated by dividing total estimated manufacturing overhead cost by estimated units of the allocation base. O d. calculated at the end of the accounting period once the actual amount of manufacturing overhead is known. e. based on estimated total manufacturing overhead costs