The direct labor rate for Plymouth Corporation is $9.00 per hour, and manufacturing overhead is applied to products using a predetermined overhead rate of $6.00 per direct labor-hour. During May, the company purchased $60,000 in raw materials (all direct materials) and worked 3,200 direct labor-hours. The Raw Materials inventory (all direct materials) decreased by $3,000 between the beginning and end of May. The Work in Process inventory on May 1 consisted of one job which had been charged with $4,000 in direct materials and on which 300 hours of direct labor time had been worked. There was no Work in Process inventory on May 31. If overhead was underapplied by $2,500 during May, the actual overhead cost for the month must have been: $23.500 $21,700 $18,500 $16,700