Servantez Manufacturing Corporation has a standard cost system in which it applies manufacturing overhead to products on the basis of standard machine-hours (MHs). The company's cost formula for variable overhead is $9.50 per MH. During the month, the actual total variable overhead was $51,300 and the actual level of activity for the period was 5,700 MHs. What was the variable overhead rate variance for the month?
A) $2,850 favorable
B) $2,850 unfavorable
C) $300 unfavorable
D) $300 favorable