Swan Company has a direct labor standard of 15 hours per unit of output, and a standard wage rate of $14.00 per hour. During March, employees worked 13,100 hours at an average rate of $14.20, producing 800 units of product. What is the direct labor efficiency variance? a) \$15,620 favorable b) $15,620 unfavorable c) $15,400 favorable d) $15,400 unfavorable