The standard costs and actual costs for factory overhead for the manufacture of 2,800 units of actual production are as follows: Standard Costs Fixed overhead (based on 10,000 hours) Variable overhead 3 hours per unit @ $0.71 per hour 3 hours per unit @ $1.93 per hour Actual Costs Total variable cost, $17,800 Total fixed cost, $8,100 The amount of the variable factory overhead controllable variance is Oa. $0 Ob. $1,588 favorable Oc. $1,588 unfavorable Od. $1,270 favorable