What does IRS stand for?

The correct answer is the Internal Revenue Service, commonly referred to as the IRS. This agency is responsible for the administration of federal tax laws in the United States, collecting taxes, processing tax returns, and enforcing tax regulations. The name accurately reflects its function: it operates internally within the federal government to manage and regulate revenue collection.

Each of the other options does not accurately represent the agency's name or its function. The "Internal Regulatory Service" and "Internal Recognition Service" do not exist as recognized federal agencies, and their names do not imply any connection to tax administration. The "International Revenue Service" suggests a focus on global revenue, which misrepresents the agency's sole jurisdiction over U.S. federal tax laws. Therefore, recognizing the Internal Revenue Service as the definitive title ensures clarity on the agency’s responsibilities and authority within the tax system.