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 Fixed overhead (based on 10,000 hours) 3 hours per unit @ $0.70 per hour Variable overhead 3 hours per unit @ $2.03 per hour Actual Costs Total variable cost, $18,100 Total fixed cost, $7,900 The total factory overhead cost variance is Oa. $6,375 favorable Ob. $4,625 favorable Oc. $4,625 unfavorable Od. $2,875 unfavorable