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: 3.6 hours per unit of N06 $ 5.40 per hour Standard direct labor-hours Standard variable overhead rate The following data pertain to the most recent month's operations during which ,700 units of product NO6C were made: 6,000 $33,080 Actual direct labor-hours worked Actual variable overhead incurred 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.) Variable overhead rate variance a. b. Variable overhead efficiency variance