Question: What is name of the bureau in the United States Department of Treasury that sets revenue rulings?

Context paragraphs:
Bureau of the Public Debt: The Bureau of the Public Debt was an agency within the Fiscal Service of the United States Department of the Treasury.  United States Secretary of the Treasury Timothy Geithner directed the Bureau be combined with the Financial Management Service into the single Bureau of the Fiscal Service in 2012.

Terrorist Screening Center: The Terrorist Screening Center (TSC) is a division of the National Security Branch of the Federal Bureau of Investigation.  It is the duty of the TSC to identify suspected or potential terrorists. Though housed within the FBI, the TSC is a multi-agency organization, including representatives from the United States Department of Justice, the United States Department of State, the United States Department of Homeland Security, the United States Department of Defense, the United States Postal Service, and various private contractors.  It is located in Vienna, Virginia, near Virginia State Route 123.

Revenue ruling: Revenue Rulings are public administrative rulings by the Internal Revenue Service (IRS) in the United States Department of the Treasury of the United States federal government that apply the law to particular factual situations.  A Revenue Ruling can be relied upon as precedent by all taxpayers.

United States Treasury security: A United States Treasury security is an IOU from the US Government.  It is a government debt instrument issued by the United States Department of the Treasury to finance government spending as an alternative to taxation.  Treasury securities are often referred to simply as Treasuries.  Since 2012 the management of government debt has been arranged by the Bureau of the Fiscal Service, succeeding the Bureau of the Public Debt.

Treasury regulations: Treasury Regulations are the tax regulations issued by the United States Internal Revenue Service (IRS), a bureau of the United States Department of the Treasury.  These regulations are the Treasury Department’s official interpretations of the Internal Revenue Code and are one source of U.S. federal income tax law.

Bureau of Prohibition: The Bureau of Prohibition (or Prohibition Unit) was the federal law enforcement agency formed to enforce the National Prohibition Act of 1919, commonly known as the Volstead Act, which elaborated upon the 18th Amendment to the United States Constitution regarding the prohibition of the manufacture, sale, and transportation of alcoholic beverages.  When it was first established in 1920, it was a unit of the Bureau of Internal Revenue.  On April 1, 1927, it became an independent entity within the Department of the Treasury, changing its name from the "Prohibition Unit" to the "Bureau of Prohibition".  In 1930, it became part of the Department of Justice.  By 1933, with the Repeal of Prohibition imminent, it was briefly absorbed into the FBI, or "Bureau of Investigation" as it was then called, and became the Bureau's "Alcohol Beverage Unit," though, for practical purposes it continued to operate as a separate agency.  Very shortly after that, once Repeal became a reality, and the only federal laws regarding alcoholic beverages being their taxation, it was switched back to Treasury, where it was renamed the Alcohol Tax Unit.

Treasurer of the United States: The Treasurer of the United States is an official in the United States Department of the Treasury who was originally charged with the receipt and custody of government funds, though many of these functions have been taken over by different bureaus of the Department of the Treasury.  Responsibility for oversight of the Bureau of Engraving and Printing, the United States Mint, and the United States Savings Bonds Division (now the Savings Bond Marketing Office within the Bureau of the Public Debt) was assigned to the Treasurer in 1981.  As of 2002 the Office of the Treasurer underwent a major reorganization.  The Treasurer now advises the Director of the Mint, the Director of the Bureau of Engraving and Printing, the Deputy Secretary and the Secretary of the Treasury on matters relating to coinage, currency and the production of other instruments by the United States.

Bureau of Engraving and Printing: The Bureau of Engraving and Printing (BEP) is a government agency within the United States Department of the Treasury that designs and produces a variety of security products for the United States government, most notable of which is Federal Reserve Notes (paper money) for the Federal Reserve, the nation's central bank.  In addition to paper currency, the BEP produces Treasury securities; military commissions and award certificates; invitations and admission cards; and many different types of identification cards, forms, and other special security documents for a variety of government agencies.  The BEP does not produce coins; all coinage is produced by the United States Mint.  With production facilities in Washington, DC, and Fort Worth, Texas, the Bureau of Engraving and Printing is the largest producer of government security documents in the United States.

Financial Management Service: The Financial Management Service (or FMS) was a bureau of the United States Department of the Treasury and provided several financial services for the federal government.  On October 7, 2012, Secretary of the Treasury Timothy Geithner issued a directive merging the FMS with the Bureau of the Public Debt to form the new Bureau of the Fiscal Service.

Internal Revenue Service: The Internal Revenue Service (IRS) is the revenue service of the United States federal government.  The government agency is a bureau of the Department of the Treasury, and is under the immediate direction of the Commissioner of Internal Revenue, who is appointed for a five-year term by the President of the United States.  The IRS is responsible for collecting taxes and administering the Internal Revenue Code, the federal statutory tax law of the U.S. Its duty to maximize tax revenue entails providing tax assistance to taxpayers, as well as pursuing and resolving instances of erroneous or fraudulent tax filings.  The IRS has also overseen various benefits programs, and enforces portions of the Affordable Care Act.

Supporting paragraphs: Revenue ruling Internal Revenue Service
Answer: Internal Revenue Service