The following standards for variable manufacturing overhead have been established for a company that makes only one product: Standard hours per unit of output 7.4 hours Standard variable overhead rate $13.80 per hour The following data pertain to operations for the last month: Actual hours Actual total variable manufacturing overhead cost Actual output 2,775 hours $38,995 200 units What is the variable overhead efficiency variance for the month? $18,571 U $17,871 U $700 U