Time to Repay a Loan.

A college graduate has $$40,000$ of student loans at $4\mathrm{.}44\%$ APR. If he repays $$600$ a month starting a month from now, how long will it take for him to repay his loans? $($Hint: calculate the months, then convert this to years.$)$

a$.7\mathrm{.}8$ years

b$.6\mathrm{.}4$ years

c$.4\mathrm{.}7$ years

d$.5\mathrm{.}4$ years

e$.9\mathrm{.}0$ years