Cost of debt. Dunder$-$Mifflin, Inc. $($DMI$)$ is selling $600,000$ bonds to raise money for the publication of new magazines in the coming year. The bond will pay a coupon rate of $12\mathrm{.}1\%$ with

semiannual payments and will mature in $30$ years. Its par value is $$100.$ What is the cost of debt to DMI if the bonds raise the following amounts $($ignoring issuing costs$)?$

a$.$ $$57,858,000$

b$.$ $$56,928,000$

c$.$ $$70,482,000$

d$.$ $$76,212,000$

$\%($Round to two decimal$$ places.$)$