When Calculating the Predetermined Manufacturing Overhead Rate, What Is the Correct

When calculating the predetermined manufacturing overhead rate, what is the correct basis of calculation?

A) Actual overhead costs of the prior year divided by the actual amount of the cost driver or allocation base
B) Estimated overhead costs divided by the estimated amount of the cost driver or allocation base
C) Estimated amount of the cost driver divided by the estimated total overhead costs
D) Estimated overhead costs divided by the number of days in a year