Which of the following is not considered taxable income?

Health insurance reimbursement is not considered taxable income because it is typically treated as a return of premiums paid by the employee or as a benefit provided by the employer. When an employer reimburses an employee for health insurance expenses, it generally does not constitute income that is subject to income tax. This is aligned with the principles of tax law that allow for certain employee benefits, particularly those related to health care, to be exempt from taxation in order to promote welfare and health coverage.

In contrast, wages, dividends, and rental income represent various forms of income that, under tax law, are subjected to taxation. Wages are payments for services rendered, dividends are a share of corporate profits distributed to shareholders, and rental income is derived from leasing property. All of these are considered taxable because they reflect economic gain that is recognized under the Internal Revenue Code.

Thus, the classification of health insurance reimbursement as non-taxable income reflects an understanding of the specific tax provisions that apply to employee benefits, distinguishing them from other forms of income that are taxable.