Courington Detalling's cost formula for its materlals and supplles is $1,910 per month plus $10 per vehicle. For the month of August, the company planned for activity of 86 vehicles, but the actual level of activity was 51 vehlcles. The actual materlals and suppliles for the month was $2430. The spending variance for materlals and supplies In August would be closest to Multiple Choice $10 F $340 F $10 U $340 U