Midgley Corporation makes a product whose direct labor standards are 1.3 hours per unit and $14.00 per hour. In April, the company produced 5,400 units using 6,540 direct labor-hours. The actual direct labor cost was $87,960. The labor efficiency variance for April is: O $6,720 U O $6,720 F O $6.639 E O $6.748 U