Wolf Manufacturing expects the following overhead costs in the current year:

Indirect material$45,000Indirect labor55,000Depreciation of machinery160,000Repair and maintenance on machinery135,000Utilities and taxes55,000Total$450,000

It expects to use 25,000 direct labor hours at a cost of $525,000 and 15,000 machine hours during the year.

Justify the selection of an appropriate allocation base.