This question is being reposted as separate individual questions because it has several portions that are not adequately answered: Please provide an explantion of how the answer is calculated. this one asks to calculate the variable overhead efficiency variance for March, answer options are below at the end of the question.Thanks

The Dudley Corporation makes and sells a single product. Overhead costs are applied on the basis of standard direct labor hours. The standard cost card shows that 5 direct labor hours are required per unit. The Dudley Corporation had the following budgeted and actual data for March:

Actual Budgeted

Units Produced 33,900 30,800

Direct Labor Hours 161,800 154,000

Variable Overhead costs 140,500 123,200

Fixed Overhead Costs 80,000 77,000

The variable overhead efficiency variance for March is:

A. $12,400 F

B. $6,160 U

C. $12,400 U

D. $6,160 F