What is an annuity?

An annuity is defined as a financial product that provides a fixed series of payments over a specific period of time, typically set up to provide income during retirement. This type of financial arrangement allows individuals to make a lump-sum payment or a series of payments that will grow and then be returned as scheduled payouts.

Annuities can be structured in several ways, such as immediate or deferred, but they fundamentally feature the reliability of regular payments. This is particularly beneficial for retirement planning, as it helps individuals to budget and manage their finances by providing a steady stream of income.

The other options do not encapsulate the primary nature of an annuity: one option talks about a payment linked only to death, while another discusses a one-time payment for a specific duration. There is also an option that refers to investments with variable payouts, which is not representative of the fixed nature of annuities. The essence of what sets an annuity apart is this structured frequency of guaranteed payments, which aligns directly with the correct answer.