9. Shelby Boat Wash's cost formula for its cleaning equipment and supplies is $2,660 per month plus $33 per boat. For the month of September, the company planned for activity of 71 boats, but the actual level of activity was 28 boats. The actual cleaning equipment and supplies for the month was $3,638 The activity variance for cleaning equipment and supplies in September would be closest to: $1,365 O $1,419 F O $1,419 U $1,365 u