Dubberly Corporation's cost formula for its manufacturing overhead is $31,400 per month plus $56 per machine-hour. For the month of March, the company planned for activity of 8,060 machine-hours, but the actual level of activity was 7,960 machine-hours. The actual manufacturing overhead for the month was $506,130. The spending variance for manufacturing overhead in March would be closest to: Multiple Choice $23,370 U $23,370 F Loooo $28,970 F $28,970 U