Which of the following is NOT an example of a qualified retirement plan?

A qualified retirement plan typically refers to a plan that meets the requirements of the Internal Revenue Code and provides tax advantages for both employees and employers. A Section 403(b) plan is actually a type of retirement plan specifically designed for employees of certain public schools and tax-exempt organizations, which qualifies it under the IRS guidelines.

The other options listed are also examples of qualified retirement plans. A profit-sharing plan allows employers to make contributions to employees' retirement accounts based on a percentage of the company's profits. An employee stock ownership plan (ESOP) provides a company's workforce with an ownership interest in the company through stock ownership. A cash balance plan is a defined benefit plan that provides a set amount of benefit upon retirement based on accumulated contributions and interest.

As such, the identification of the Section 403(b) plan in this context highlights its distinct classification among retirement plans eligible for tax advantages but does not align with the question's scope of qualified retirement plans compared to the other examples listed.