Dunder$-$Mifflin, Inc. hires an investment banker for the sale of the $600,000$ bonds from Problem $4.$ The investment banker charges a $2\%$ fee on each bond sold. What is the cost of debt to DMI if the following are the proceeds before the banker's fees are deducted?

$$54,000,000?$

$13\mathrm{.}64\%$

$15\mathrm{.}38\%$

$13\mathrm{.}04\%$

$14\mathrm{.}84\%$

$11\mathrm{.}52\%$