Answer:
a. Secured bonds - A secured bond is a bond that is issued with a collateral backing the loan.
b. Callable bonds - A bond that the issuer can call off, or pay off, at any time, not necessarily at maturity.
c. Convertible bonds - A bond that can be converted into equity (stocks). If the bondholder wishes, he can exchange his bond for ownership of stocks in the bond issuer firm.
d. Term bonds - A bond that has one single, specific maturity date.
e. Serial bonds - A bond that has several maturity dates.