Use this information for Bonny Company to answer the question that follows.

The standard costs and actual costs for factory overhead for the manufacture of 2,500 units of actual production are as follows:

Standard CostsFixed overhead (based on 10,000 hours)3 hours per unit @ $0.72 per hourVariable overhead3 hours per unit @ $1.93 per hourActual Costs Total variable overhead cost, $18,000 Total fixed overhead cost, $8,000

The variable factory overhead controllable variance is

a. $3,525 favorable

b. $2,820 favorable

c. $0

d. $3,525 unfavorable