Onyx Company Has Prepared a Static Budget at the Beginning

Onyx Company has prepared a static budget at the beginning of the month. At the end of the month, the following information has been retrieved from the records. Static budget:
Sales volume: 1,000 units: Price: $70 per unit
Variable expense: $32 per unit: Fixed expenses: $37,500 per month
Operating income: $500
Actual results:
Sales volume: 990 units: Price: $74 per unit
Variable expense: $35 per unit: Fixed expenses: $33,000 per month
Operating income: $5,610
Calculate the sales volume variance for revenues.

A) $4,500 U
B) $700 U
C) $380 U
D) $3,960 F