Kropf Inc. has provided the following data concerning one of the products in its standard cost system. Variable manufacturing overhead is applied to products on the basis of direct labor-hours. Standard Quantity or Hours per Unit of Output 8.10 liters Inputs Direct materials Standard Price or Rate $ 7.70 per liter $28.70 r hou $ 6.60 per hour O.40 hours 0.40 hours Direct labor Variable manufacturing overhead The company has reported the following actual results for the product for September: Actual output Raw materials purchased Actual cost of raw materials purchased Raw materials used in production Actual direct labor-hours I0.300 units 75.700 liters $607,500 83.460 liters 3,840 hours Actual direct labor cost 15.302 $ 20,314 Actual variable overhead cost Required: a. Compute the materials price variance for September. b. Compute the materials quantity variance for September. c. Compute the labor rate variance for September. d. Compute the labor efficiency variance for September. (Input all amounts as positive values.) Materials price variance a. b. Materials quantity variance Labor rate variance C. Labor efficiency variance d