S received a lump sum retirement buyout and wants an annuity for guaranteed income for life; what type of annuity should she consider?

In the scenario where S received a lump sum retirement buyout and desires guaranteed income for life, the most suitable option is an immediate annuity. An immediate annuity allows an individual to convert a lump sum amount into a stream of income that begins almost immediately, typically within a month of purchase. This aligns perfectly with S's goal of receiving guaranteed income without delay.

By purchasing an immediate annuity, S can lock in a fixed monthly payment that will continue for her entire lifetime or for a specified period, providing financial security during retirement. It is ideal for individuals looking for steady income without the need to wait for any accumulation period, which is characteristic of other types of annuities.

In contrast, a deferred annuity would not begin paying out income immediately, as it is designed for accumulation of funds and typically starts distributions at a later date, making it less suitable for S's immediate income needs. A flexible installment deferred annuity also focuses on deferring payments and allows for payment flexibility but does not address the immediate need for income. Therefore, the best choice for S to achieve her goal of guaranteed income for life right after her lump sum retirement buyout is the immediate annuity.