Which of the following best fits under the umbrella of "ordinary income" according to IRS guidelines?

Ordinary income refers to the earnings that an individual or business receives from normal business operations and various sources of income, as defined by IRS guidelines. Revenues derived from operational activities represent money earned through the sale of goods or services that a business offers in the regular course of its operations. This includes salaries, wages, commissions, and business profits, which are typically taxed at ordinary income tax rates.

In contrast, capital gains from investments are considered investment income and are taxed differently, often at preferential long-term capital gains rates. Gift income and inheritances are also not classified as ordinary income; they may be subject to different types of taxation, such as gift or estate tax, rather than income tax. Therefore, revenues derived from operational activities align with the definition of ordinary income and is the correct choice.