Ruston Corporation applies manufacturing overhead to products on the basis of standard machine-hours. Budgeted and actual overhead costs for the most recent month appear below:

The original budget was based on 4,500 machine-hours. The company actually worked 4,590 machine-hours during the month and the standard hours allowed for the actual output were 4,700 machine-hours. What was the overall variable overhead efficiency variance for the month?

A. $969 unfavorable

B. $100 unfavorable

C. $50 unfavorable

D. $869 favorable