Larance Detailing's cost formula for its materials and supplies is $2,230 per month plus $1 per vehicle. For the month of November, the company planned for activity of 75 vehicles, but the actual level of activity was 25 vehicles. The actual materials and supplies for the month was $2,160. The activity variance for materials and supplies in November would be closest to: $145 U $145 F $50 F $50 U