need confrimation if this answer is right, or if it is one of the other answers

Dubberly Corporation's cost formula for its manufacturing overhead is $31,600 per month plus $52 per machine-hour. For the month of March, the company planned for activity of 8,100 machine-hours, but the actual level of activity was 7980 machine-hours. The actual manufacturing overhead for the month was $476,410. The activity variance for manufacturing overhead in March would be closest to: Multiple Choice $23,610 U $23,610 F $6.240 F $6,240 U