The following standards for variable manufacturing overhead have been established for a company that makes only one product: Standard hours per unit of output Standard variable overhead rate 7.2 hours $13.60 per hour The following data pertain to operations for the last month: Actual hours Actual total variable manufacturing overhead cost Actual output 2,750 hours $38,090 250 units What is the variable overhead efficiency variance for the month? Multiple Choice $13.610 U $12,920 U $690 U $24.480 F