Freytag Corporation's variable overhead is applied on the basis of direct labor-hours. The company has established the following variable overhead standards for product NO6C: Standard direct labor-hours Standard variable overhead rate 3.5 hours per unit of N06C $ 5.20 per hour The following data pertain to the most recent month's operations during which 1,500 units of product NO6C were made: Actual direct labor-hours worked Actual variable overhead incurred 5,100 $ 27,540 Required: a. What was the variable overhead rate variance for the month? b. What was the variable overhead efficiency variance for the month? (Indicate the effect of each variance by selecting "F" for favorable, "U" for unfavorable, and "None" for no effect (i.e., zero variance). Input all amounts as positive values.) a. Variable overhead rate variance b. Variable overhead efficiency variance