Schriever Corporation Is an Oil Well Service Company That Measures

Schriever Corporation is an oil well service company that measures its output by the number of wells serviced. The company has provided the following fixed and variable cost estimates that it uses for budgeting purposes.
The number of wells serviced in the planning budget is missing from the given information - this information is necessary to complete the calculations in the subsequent questions.
The planning budget for May was based on 36 wells serviced, but aA total of 31 wells were actually serviced during May.
-The activity variance for total expenses for May would have been closest to:

A) $10,500 F
B) $8,500 F
C) $10,500 U
D) $8,500 U