The Static Budget,at the Beginning of the Month,for Singleton Company

The static budget,at the beginning of the month,for Singleton Company follows: Static budget:
Sales volume: 1,000 units; Sales price: $70.00 per unit
Variable costs: $33.00 per unit; Fixed costs: $36,500 per month
Operating income: $500
Actual results,at the end of the month,follows:
Actual results:
Sales volume: 980 units; Sales price: $74.00 per unit
Variable costs: $35.50 per unit; Fixed costs: $34,100 per month
Operating income: $3,630
Calculate the flexible budget variance for fixed costs.

A) $2,400 U
B) $2,400 F
C) $0
D) $3,870 F