Which of the following statements is CORRECT?

		When calculating the cost of preferred stock, a company needs to adjust for taxes, because preferred stock dividends are deductible by the paying corporation.
		All else equal, an increase in a companys stock price will increase its marginal cost of retained earnings.
		Since the money is readily available, the after-tax cost of retained earnings is usually much lower than the after-tax cost of debt.
		If a companys tax rate increases, the after-tax cost of its debt will fall.