Which agency is primarily focused on tax collection in the USA?

The Internal Revenue Service (IRS) is primarily focused on tax collection in the USA. As a bureau of the Department of the Treasury, the IRS is responsible for administering and enforcing the federal tax laws, ensuring that taxpayers comply with their obligations, and collecting revenue for the federal government. The agency handles individual income tax returns, business taxes, and a variety of other tax-related issues, making it the central authority on taxation in the United States.

While the Department of the Treasury oversees the IRS, it has a broader mandate that includes managing federal finances, regulating financial institutions, and producing currency. The other options, such as NASA and the FBI, serve entirely different functions related to space exploration and law enforcement, respectively, and are not involved in tax collection or financial administration.