18) The following standards for variable manufacturing overhead have been established for product a company that makes only one Standard hours per unit of output 6.6 hours 13.00 per hour Standard variable overhead rate The following data pertain to operations for the last month Actual hours 2675 hours $ 35,435 Actual total variable manufacturing overhead cost Actual output 250 units What is the variable overhead efficiency variance for the month? B) $21,450 F C) $13,985 U A) $660 U D) $13,325 U