The following is monthly budgeted cost and activity information for two activities in the purchasing department of X Company: Activity Supplier relations Invoicing Variable Fixed Cost Costs Costs Driver 230 $5,750 $16,400 suppliers 810 $9,720 $23,200 invoices In November, actual costs and activity were as follows: Total Driver Activity Costs Amount Supplier relations 175 $21,643 suppliers Invoicing $32,948 831 invoices What was the flexible budget variance for the invoicing activity for November (assume that favorable variances are positive numbers and unfavorable variances are negative numbers)? A: $-23,228 B: $-22,976 C: $-9,748 D: $-28 E: $0 F: $224