The following standards for variable manufacturing overhead have been established for a company that makes only one product:

Standard hours per unit of output	7.8	hours
Standard variable overhead rate	$14.20	per hour

The following data pertain to operations for the last month:

Actual hours	2,825	hours
Actual total variable manufacturing overhead cost	$40,835
Actual output	250	units

What is the variable overhead efficiency variance for the month?

$13,145 U

$12,425 U

$720 F

$27,690 F