Use this information to answer the question that follow. The standard costs and actual costs for factory overhead for the manufacture of 2,500 units of actual production are as follows: Standard Costs 3 hours per unit @ $0.74 per hour 3 hours per unit @ $1.92 per hour Fixed overhead (based on 10,000 hours) Variable overhead Actual Costs Total variable cost, $18,100 Total fixed cost, $8,000 The total factory overhead cost variance is Oa. $7,400 favorable Ob. $5,550 unfavorable Oc. $5,550 favorable Od. $3,700 unfavorable