Onyx Décor Company Has Prepared a Static Budget at the Beginning

Onyx Décor Company has prepared a static budget at the beginning of the month.At the end of the month,following information has been retrieved from the records. Static budget:
Sales volume: 2,000 units: Price: $50 per unit
Variable expense: $12 per unit: Fixed expenses: $25,000 per month
Operating income: $51,000
Actual results:
Sales volume: 1,800 units: Price: $58 per unit
Variable expense: $16 per unit: Fixed expenses: $35,000 per month
Operating income: $40,600
Calculate the flexible budget variance for operating income.

A) $4,500 U
B) $7,600 U
C) $2,800 U
D) $5,490 F