The Montgomery Corporation has a standand costing system in which variable o production on the basis of standard manufacturing overhead is assigned 3,000 hours 3,420 Unfavorable machine-hours The following data are available for September production$22,620 Standard machine-hours allowed for September Actual variable manufacturing overhead cost incurred Variable overhcad rate variance Total variable overhead spending variance $4,620 Unfavorable 12 Actual machine-hours worked during September is 3,000 hours 3,200 hours 3,300 hours 3,770 hours E None of the above