Which of the following parents' payment structure can be described as an annuity?

An annuity is a series of equal payments made at regular intervals, typically involving financial products that provide predictable income over time. In the context of the question, if both Jack and Brian provide payments that are consistent in amount and frequency, then their payment structures can indeed be characterized as annuities.

For a payment structure to be deemed an annuity, it must meet these specific criteria: the payments must be equal, they must occur at regular intervals (such as annually, semi-annually, or monthly), and the term should typically have a set duration.

The determination that both Jack and Brian have payment structures fitting this description means they are likely both making equal payments at regular intervals. This uniformity makes it possible to accurately classify their payment structures as annuities, thus justifying the selection of both as the correct answer.

If Bill's structure does not conform to these characteristics—whether through variability in payment amounts, irregular payment intervals, or a lack of continuity in payments—he would not fit the annuity definition. This distinction explains why Jack and Brian are emphasized as the correct choice.