Icy Mocha Company estimates its factory overhead costs to be $$32,000$ and machine hours to be $4,000$ for the year. If the actual hours worked on Job No$.333$ and Job No$.334$ total $3,970$ and actual factory overhead costs are $$31,620,$ what is the amount of either over$-$ or underapplied factory overhead?

a$.$ Underapplied $$310$

b$.$ Overapplied $$310$

c$.$ Underapplied $$140$

d$.$ Overapplied $$140$