For a customer interested in maximizing retirement income with a $100,000 immediate annuity, which option pays the largest monthly amount?

Choosing a life-only immediate annuity option allows the customer to receive the largest monthly payment because this option guarantees monthly payments for the lifetime of the annuitant without any further conditions or benefits that could reduce the payout amount.

In a life-only annuity, the payments cease upon the death of the annuitant, meaning that the insurance company does not have to reserve funds for future payments beyond the annuitant's lifetime. This provides the maximum payout since the risk of paying out benefits for a longer term is minimized for the insurer. The absence of any additional provisions, such as refund guarantees or survivor benefits, directly translates into a higher benefit amount for the annuitant.

In contrast, other options like life with installment refund or joint with survivor options provide additional security for beneficiaries or ensure that a certain amount will be paid out, which decreases the monthly payment to the annuitant because the insurer must account for these additional obligations. Similarly, the life only with a 10-year period certain option guarantees payments for at least ten years but still involves lower monthly payouts than the straightforward life-only option due to the reserving of funds for that guaranteed period.

Thus, for someone looking to optimize their monthly income without concern for beneficiaries or minimum payout guarantees