Use this information to answer the question that follow. The standard costs and actual costs for factory overhead for the manufacture of 2,600 units of actual production are as follows Fixed overhead (based on 10,000 hours) Variable overhead 3 hours per unit$0.75 per hour 3 hours per unit $1.95 per hour Total variable cost, $18,200 Total fixed cost, $8,200 The fixed factory overhead volume variance is Oa. $1,320 unfavorable Ob. $0 Oc.$1,650 unfavorable Od. $1,320 favorable