Willis Corporation manufactures industrial-sized gas furnaces and uses budgeted machine-hours to allocate variable manufacturing overhead. The following information pertains to the company's manufacturing overhead data: Budgeted output Budgeted machine-hours 30,000 units 10,000 hours Budgeted variable manufacturing overhead costs for 30,000 units Actual output produced Actual machine-hours used Actual variable manufacturing overhead costs What is the variable overhead rate variance? $322,500 44,000 units 14,400 hours $484,000 Select one: a $13,611 Favorable Ob. $13,611 Unfavorable c. $19,600 Unfavorable d. $19,600 Favorable