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 3,000 units of actual production are as follows: Standard Costs Fixed overhead (based on 10,000 hours) 3 hours per unit @ $0.77 per hour Variable overhead 3 hours per unit @ $1.91 per hour Actual Costs Total variable cost, $18,100 Total fixed cost, $8,000 The total factory overhead cost variance is Oa. $2,450 favorable Ob. $1,680 unfavorable Oc. $1.680 favorable Od. $910 unfavorable