The following is monthly budgeted cost and activity information for two activities in the purchasing department of X Company: Activity Supplier relations Invoicing Variable Costs $8,640 $9,240 Fixed Costs $15,400 $24,700 Cost Driver 360 suppliers 770 invoices In November, actual costs and activity were as follows: Activity Supplier relations Invoicing Total Costs $24,104 $34,878 Driver Amount 335 suppliers 816 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: $-25,638 | OB: $-25,086| OC: $-10,178|| OD: $-938|| OE: $-386|| OF: $0