How Do You Calculate the Predetermined Manufacturing Overhead Rate Used

How do you calculate the predetermined manufacturing overhead rate used to allocate manufacturing overhead costs?

A) By dividing the total estimated manufacturing overhead costs by the total estimated amount of the allocation base
B) By dividing the total estimated amount of the allocation base by the total estimated manufacturing overhead costs
C) By dividing the total estimated manufacturing overhead costs by the total actual amount of the allocation base
D) By multiplying the total estimated manufacturing overhead costs by the total estimated amount of the allocation base