The following information summarizes the standard cost for producing one metal tennis racket frame at Spaulding Industries. In addition, the variances for one month's production are given. Assume that all inventory accounts have zero balances at the beginning of the month.

Standard Cost Per UnitStandard Monthly CostsMaterials$5.00$9,700Direct Labor 3 hrs. @ $2.808.4023,520Factory Overhead:Variable1.805,040Fixed5.5015,400$20.70$53,660

Variances:Material price210.00unfavorableMaterial quantity800.00unfavorableLabor rate630.00favorableLabor efficiency2,520.00unfavorable

What were the actual direct labor hours worked during the month?

a8,400.

b9,075.

c9,300.

d8,175.