Borunda Air uses two measures of activity, flights and passengers, in the cost formulas in its budgets and performance reports. The cost formula for plane operating costs is $46,500 per month plus $2,965 per flight plus $14 per passenger. The company expected its activity in July to be 156 flights and 321 passengers, but the actual activity was 158 flights and 319 passengers. The actual cost for plane operating costs in July was $507,160. The activity variance for plane operating costs in July would be closest to:

A:$6,374 F

B:$5,902 F

C:$6,374 U

D:$5,902 U