Standard hours per unit of output8.

Hi I need help with this question

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

  Standard hours per unit of output8.0  hours  Standard variable overhead rate$14.40  per hour 

The following data pertain to operations for the last month: 

  Actual hours2,850  hours  Actual total variable manufacturing overhead cost$41,770    Actual output200  units

What is the variable overhead efficiency variance for the month? 

$18,730 U

$18,000 U

$730 F

$23,040 F