$63$

$66$

$--$

$69$

$--$

$72$

$--$

$75$

$--$

$78$

$81$

$84$

A firm's aftertax cost of debt will increase if there is a$($n$)$:

$$decrease in the company's debt$-$equity ratio.

$$decrease in the company's tax rate.

$$increase in the credit rating of the company's bonds.

$$increase in the company's beta.

$$decrease in the market rate of interest.