What type of bond would require a call premium when the issuer decides to redeem early?

A callable bond includes a feature that allows the issuer to redeem the bond before its maturity date. When the issuer chooses to do this, they often pay a call premium to compensate bondholders for the early redemption. This premium is an additional payment on top of the face value of the bond and serves as an incentive for investors, as it mitigates the loss from interest payments that would have continued if the bond had remained outstanding until maturity.

In the context of other types of bonds, convertible bonds and convertible debentures provide the option for bondholders to convert their bonds into equity, but they don't inherently involve a call premium related to early redemption. Zero coupon bonds, being sold at a discount and paying no periodic interest, do not typically include call features that require payment of premiums upon early redemption. Thus, the primary characteristic of callable bonds that necessitates a call premium solidifies why this answer is the most accurate in this scenario.