Answer the Following Questions Using the Information Below:
Russo Corporation

Answer the following questions using the information below:
Russo Corporation manufactured 16,000 air conditioners during November. The overhead cost-allocation base is $31.50 per machine-hour. The following variable overhead data pertain to November:
$$\begin{array} { l r r } & \text { Actual } & \text { Budgeted } \\\text { Production }& 16,000 \text { units } & 18,000 \text { units } \\\text { Machine-hours } & 7,875 \text { hours }& 9,000 \text { hours } \\\text { Variable overhead cost per machine-hour: } &\$ 31.00 & \$ 31.50\end{array}$$
-What is the variable overhead efficiency variance?

A) $3,937.50 favorable
B) $3,937.50 unfavorable
C) $4,500 favorable
D) $4,500 unfavorable