Novelli Corporation makes a product whose variable overhead standards are based on direct labor-hours. The quantity standard is 0.6 hours per unit. The variable overhead rate standard is $5.00 per hour. In September the company produced 1,600 units using 950 direct labor-hours. The actual variable overhead rate was $5.10 per hour. The variable overhead efficiency variance for September is:

A.) $51 U

B.) $50 U

C.) $51 F

D.) $50 F