Part $1$

Attempt $1/2$ for $1$ pts$.$

Which of the following statements is correct?

The cash flows for an annuity must all be equal, and they must occur at regular intervals, such as every quarter or every year.

A series of unequal cash flows that occur at regular intervals, such as every quarter, is an annuity.

The cash flows for an annuity due all occur at the ends of the periods.

The cash flows for an ordinary annuity all occur at the beginning of the periods.