Armour, Inc., an advertising agency, applies overhead to jobs on the basis of direct professional labor hours. Overhead was estimated to be $216,000, direct professional labor hours were estimated to be 18,000, and direct professional labor cost was projected to be $270,000. During the year, Armour incurred actual overhead costs of $212,000, actual direct professional labor hours of 17,500, and actual direct labor cost of $317,000. By year-end, the firm's overhead was:

a. $2,000 underapplied.
b. $6,000 underapplied.
c. $4,000 underapplied
d. $2,000 overapplied
e. $4,000 overapplied.