Answer:
A. We can use Modigliani and Miller's first proposition to derive an explicit relationship between leverage and the equity cost of capital.
Explanation:
Their main conclusions can be summarized as: In the absence of taxes, firm capital structure is irrelevant. With taxes, a firm's cost of capital can be lowered through issuing debt. This highlights the importance of debt as a tax shield.
Modigliani and Miller's conclusion went against the common view that even with perfect capital markets, leverage would affect a firm's value.