A Roth IRA is designed to provide tax-free qualified withdrawals, which makes A correct. With a Roth IRA, contributions are generally made with after-tax dollars (no up-front tax deduction), but if the investor meets the qualified distribution rules—typically satisfying the 5-year aging requirement and taking distributions after meeting an eligible reason such as reaching the applicable retirement age threshold—withdrawals of earnings can be tax-free. The question’s key phrase is “tax-free withdrawals when they retire,” which points directly to Roth treatment.

A Traditional IRA (choice B) generally provides tax benefits upfront (potential deductibility of contributions, depending on income and plan coverage), but distributions are typically taxed as ordinary income when withdrawn. SEP IRAs (choice C) and SIMPLE IRAs (choice D) are employer-sponsored IRA arrangements designed for small businesses and employee retirement savings. While they are retirement accounts, their tax treatment is generally similar to traditional arrangements—contributions are typically pre-tax (or tax-deductible to the employer), and withdrawals are generally taxable. They do not match the “tax-free withdrawals” objective as cleanly as the Roth IRA.

On the SIE, the high-level distinction is: Roth = tax now, tax-free later (if qualified); Traditional/SEP/SIMPLE = tax benefit now, taxed later. The customer’s age (50) and time horizon (15 years) also fits the typical framework that they can potentially satisfy the Roth holding period requirements by retirement.