Answer: serial bond
Step-by-step explanation:
Serial bonds are bonds that mature at more than one date with the result that the principal amount is repaid over a number of periods.
A serial bond is a bond that has been structured in such a way that portions of the bonds will have to mature at regular intervals until the moment that the bonds have all matured.
Due to the fact that the bonds have to mature gradually with time for certain years, the bonds are typically used to finance projects.