Adjusted WACC.

Lewis runs an outdoor adventure company and wants to know what effect a tax change will have on his company's WACC. Currently, Lewis has the following financing pattern:

Equity:26% and cost of 18.71%

Preferred stock:19% and cost of 12.31%

Debt:55% and cost of 10.8% before taxes

What is the adjusted WACC for Lewis if the tax rate is

a.

40%?

b.

30%?

c.

15%?

d.

5%?

e.

0%?