Mondo Snow Removal's cost formula for its vehicle operating cost is $1,340 per month plus $630 per snow-day. For the month of January, the company planned for activity of 29 snow-days, but the actual level of activity was 33 snow-days. The actual vehicle operating cost for the month was $21,790. The activity variance for vehicle operating cost in January would be closest to:

$2,520U

$2,180F

$2,180U

$2,520F