Bonnie Company has a direct labor standard of 15 hours per unit of output. Each employee has a standard wage rate of $14 per hour. The standard variable overhead rate is $10 per hour. During March, employees worked 13,100 hours. The direct labor rate variance was $9,170 favorable, the variable overhead rate variance was $13,100 unfavorable, and the direct labor efficiency variance was $15,400 unfavorable. What is the variable overhead efficiency variance? $13,100 unfavorable $11,000 unfavorable $24,100 unfavorable $11,000 favorable