Explain and give me a correct answer!

Courington Detailing's cost formula for its materials and supplies is $1,890 per month plus $8 per vehicle. For the month of August, the company planned or activity of 84 vehicles, but the actual level of activity was 49 vehicles. The actual materials and supplies for the month was $2,450. The actlvity varlance for materlals and supplles In August would be closest to: Multiple Choice $280 $112U $112F $280F