The standard costs and actual costs for factory overhead for the manufacture of 2,500 units of actual production are as follows: Standard Costs Fixed overhead (based on 10,000 hours) 3 hours per unit at $0.71 per hour Variable overhead 3 hours per unit at $1.92 per hour Actual Costs Total variable cost, $18,000 Total fixed cost, $7,800 The variable factory overhead controllable variance is Oa. $3,600 favorable Ob. 52,880 favorable Oc. $3,600 unfavorable Od. 60