Lopata Manufacturing uses a standard cost system for its guitar boxes. The standard labor rate per box is $1 per box. This standard was established on the basis of producing 8 boxes per hour. This month, Lopata produced 1,500 boxes using 580 direct labor hours at an actual direct labor cost of $5,800. The direct labor rate variance was:
a) $1,600 favorable
b) $1,160 favorable
c) $1,600 unfavorable
d) $1,160 unfavorable