James Manufacturing had the following information available for July: Flexible Sales Actual Flexible Master Budget Results Activity Variance Budget Budget Variance Units 11,500 ? 4,000 U? Sales revenue ? $ 14,000 F ? ? ? Less: Variable $ 88,750 ? $ 93,000 manufacturing costs $ 113,000 Variable marketing ? and administrative $ 6,250 U ? $ 7,000 F $ 34,000 Contribution margin $ 53,000 ? ? $ 6,400 U ? What was James's activity variance for variable manufacturing costs? $33,400 $4,250 $20,000 $40,600