Which of the following is an example of an employer-sponsored retirement plan?

An employer-sponsored retirement plan is designed to help employees save for retirement effectively, typically with contributions facilitated by their employer. A 401(k) plan is a prime example of this type of plan. It allows employees to contribute a portion of their pre-tax income to the account, often supplemented by employer contributions, such as matching contributions. This not only promotes saving for retirement but also offers tax advantages that can enhance the growth of the savings over time.

The other options represent different financial instruments. A Roth IRA is an individual retirement account that one can establish independently and does not involve an employer's contribution. A traditional savings account is a standard bank account that earns interest, lacking any specific retirement features. Lastly, a Health Savings Account (HSA) is designed for medical expenses and is not categorized as a retirement plan. Thus, the 401(k) plan uniquely qualifies as an employer-sponsored retirement plan.