Answer:
C. An annuity is an investment plan that guarantees payments at regular intervals after retirement.
Step-by-step explanation:
Let us see our given choices one by one.
A. A retirement plan offered by employers.
As annuities are generally offered by insurance companies, therefore, option A is not a correct choice.
B. Since a group of investments that many individual investors hold in common is called mutual funds, therefore, option B is not a correct choice.
C. An investment plan that guarantees payments at regular intervals after retirement.
Since we know that annuity is a fixed amount of money paid to someone each year for the rest of their life. Annuities are primarily used as an income stream for retirees, therefore, option C is the correct choice.