What does IRS stand for?

The term IRS stands for Internal Revenue Service, which is the federal agency in the United States responsible for administering the nation's tax laws and collecting federal taxes. The agency plays a crucial role in enforcing tax compliance and processing tax returns from individuals and businesses.

The Internal Revenue Service is responsible for a range of functions including providing guidance on tax regulations, processing tax documents, collecting taxes owed, and issuing refunds. Understanding the role and operations of the IRS is important for individuals and businesses alike, as it directly affects tax obligations and financial planning.

In contrast, the other options do not relate to recognized government agencies or relevant financial terms. Independent Revenue Source, Internal Ratio Structures, and I Really Stink do not accurately represent any established terminology or agency-related functions concerning taxation, thus making Internal Revenue Service the correct response in this context.