In a World with Corporate Taxes but No Bankruptcy Costs

In a world with corporate taxes but no bankruptcy costs,

A) the firm value is unaffected by capital structure.
B) the firm should maximize the value of the firm by maximizing the firm's debt.
C) the firm should borrow to the point just below where the marginal benefits of debt equal the marginal costs.
D) the firm cannot make a decision about its optimal capital structure with the existing information.