Correct answer:
c. an agreement in which an investor loans money to a company or government, and the company or government promises to repay the loan with interest over a period of time.
Bonds are bought and sold in the bond market (as opposed to the stock market). The bond market consists of the government issuing securities to those who lend money for government projects, as well as corporations taking on debt and issuing securities so that they can raise money for projects or expansions.