The standard costs and actual costs for factory overhead for the manufacture of 2,800 units of actual production are as follows: Fixed overhead (based on 10,000 hours) Variable overhead Actual Costs Total variable cost, $18,200 Standard Costs 3 hours per unit at $0.75 per hour 3 hours per unit at $1.93 per hour Total fixed cost, $8,100 The variable factory overhead controllable variance is Oa. $0 Ob. $1,590 favorable Oc. $1,988 favorable Od. $1,988 unfavorable