When allocating service department costs, companies should use:

Actual costs rather than budgeted costs, and separate rates for variable and fixed costs.

Budgeted costs rather than actual costs, and separate rates for variable and fixed costs.

Budgeted costs rather than actual costs, and a rate that combines variable and fixed costs.

Actual costs rather than budgeted costs, and a rate that combines variable and fixed costs.

A rate that is based on matrix theory.