A Firm's Cost of Debt Often Differs from the Yield

A firm's cost of debt often differs from the yield reported on its bonds because

A) the firm's cost of debt is unknown when the bonds are first sold.
B) the underwriting costs for new bond issues are not tax deductible, raising the cost of debt relative to bond yields.
C) the cost of debt changes infrequently since bond rating agencies do not change their recommendations often.
D) the interest paid on corporate bonds is tax deductible.
E) speculators can drive the cost of debt down so that bond yields exceed it.