Review the following statements and select the one which is true regarding an ordinary annuity.
A. An ordinary annuity is the future value of a single sum of $1 invested for a defined number of periods at a defined interest rate.
B. An ordinary annuity is a series of equal payments occurring at the end of the period at equal intervals.
C. An ordinary annuity is is the present value of an investment for a specified number of periods at a specified interest rate.