Final answer:
The true statement about Roth 401(k)s is that employers must maintain Roth 401(k) contributions in a separate account. While contributions from employees are after-tax, employer contributions remain pre-tax. Roth 401(k)s do have required minimum distributions and are not subject to MAGI limits.
Step-by-step explanation:
The correct answer to the question regarding Roth 401(k)s is option c: The employer must maintain Roth 401(k) contributions in a separate account. This is because Roth 401(k) contributions are after-tax funds, and keeping them separate from pre-tax 401(k) contributions simplifies the tax situation. It's also important to note that while employee contributions to a Roth 401(k) are made with after-tax dollars, employer contributions are still made with pre-tax dollars and are kept in a separate account within the 401(k) plan.
Unlike Traditional 401(k)s, Roth 401(k)s do have required minimum distributions (RMDs) starting at age 72, which makes option a incorrect. Also, contributions to Roth 401(k)s do not have Modified Adjusted Gross Income (MAGI) limits like Roth IRAs do, which eliminates option b as a correct response. Finally, as mentioned earlier, only the employee's Roth 401(k) contributions are after-tax, and the employer's are pre-tax, so option d is incorrect.