A $10-$year municipal bond yields $4\mathrm{.}8\%.$ Your marginal tax rate $($including state and federal

taxes$)$ is $27\%.$ What interest rate on a $10-$year corporate bond of equal risk would provide you

with the same after$-$tax return?

a$.3\mathrm{.}50\%$

b$.6\mathrm{.}25\%$

c$.6\mathrm{.}58\%$

d$.6\mathrm{.}90\%$