Concept:An irredeemable bond has no maturity date, so the issuer pays interest forever but never repays the principal.Explanation:A redeemable bond has a fixed maturity date when the capital is repaid.A development bond and a long-term loan also involve eventual repayment of the capital.An irredeemable bond, however, provides a perpetual stream of interest only.The capital remains unpaid because there is no date for redemption.Answer:D. an irredeemable bond