Suppose Goodyear Tire and Rubber Company has an equity cost of capital of $8\mathrm{.}1\%,$ a debt cost of capital of $6\mathrm{.}6\%,$ a marginal corporate tax rate of $22\%,$ and a$$ debt$-$equity ratio of $2\mathrm{.}5.$ Assume that Goodyear maintains a constant$$ debt$-$equity ratio.

a$.$ What is$$ Goodyear's WACC?

b$.$ What is$$ Goodyear's unlevered cost of$$ capital?$$

c$.$ Explain, intuitively, why$$ Goodyear's unlevered cost of capital is less than its equity cost of capital and higher than its WACC.