When using WACC, the correct number is the: a. post-tax cost of debt, because dividends are tax-deductible. b. pre-tax cost of debt, because it is the actual rate the firm is paying bondholders. C. post-tax cost of debt, because interest is tax-deductible. Ignoring taxes and all else held constant, on the dividend. the market value of a stock should decrease by the amount of the a. ex-dividend date b. dividend declaration date C. date of payment