Which of the following expenses is considered a non-deductible business expense?

In the context of business expenses, a family vacation is classified as a non-deductible expense because it is considered a personal expenditure rather than a necessary cost incurred in the course of operating a business. The Internal Revenue Service (IRS) allows deductions for expenses that are both ordinary and necessary for carrying out the trade or business. Since a family vacation does not serve a business purpose or contribute to generating revenue for the business, it cannot be deducted from taxable income.

On the other hand, business office supplies, employee salaries, and rental expenses are directly related to the operations of a business and are deemed necessary for its functioning. These expenses are essential for running the business, making them deductible when calculating taxable income. Thus, identifying personal expenses like family vacations is key when distinguishing between what can be expensed against business income and what cannot.