Indicate which of the following statements is true about annuities:

An ordinary annuity is an equal payment paid or received at the beginning of each period. An annuity due is a payment paid or received at the beginning of each period that increases by an equal amount each period. An annuity due is an equal payment paid or received at the beginning of each period. An ordinary annuity is an equal payment paid or received at the end of each period that increases by an equal amount each period.