Porter Company Uses Standard Costs for Its Manufacturing Division At the End of the Year,actual Data Were as Follows

Porter Company uses standard costs for its manufacturing division.Standards specify 0.1 direct labor hours per unit of product.The allocation base for variable overhead costs is direct labor hours.At the beginning of the year,the static budget for variable overhead costs included the following data: $$\begin{array} { | l | l | } \hline \text { Production volume } & 5000 \text { units } \\\hline \text { Budgeted variable overhead costs } & \$ 16,000 \\\hline \text { Budgeted direct labor hours (DLHr) } & 500 \text { hours } \\\hline\end{array}$$ At the end of the year,actual data were as follows:
$$\begin{array} { | l | l | } \hline \text { Production volume } & 4100 \text { units } \\\hline \text { Actual variable overhead costs } & \$ 15,200 \\\hline \text { Actual direct labor hours (DLHr) } & 500 \text { hours } \\\hline\end{array}$$ What is the variable overhead efficiency variance? (Round any intermediate calculations to the nearest cent,and your final answer to the nearest dollar.)

A) $2400 F
B) $2400 U
C) $2736 F
D) $2736 U