4. (15 points) 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. Inputs Direct materials Direct labor Variable manufacturing overhead Standard Quantity or Hours per Unit of Output 7.3 liters 0.80 hours 0.80 hours Standard Price or Rate $ 7.10 per liter $21.20 per hour $ 5.30 per hour 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 Actual direct labor cost Actual variable overhead cost 9,600 units 74,000 liters $562,500 71,000 liters 6,410 hours $140,300 $ 35,614 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. e. Compute the variable overhead rate variance for September. f. Compute the variable overhead efficiency variance for September. (Note: You need indicate whether the variances are favorable or unfavorable.)