27. Administrative sources of the tax law, such as IRS Regulations, Revenue Rulings and Revenue Procedures: a. are generally drafted by the Supreme Court. b. are official interpretations of the tax law made by the Department of the Treasury and the IRS. c. do not have the force of law because they are the opinions of the Secretary of the Treasury. d. All of the above. 28. Decisions of federal courts on cases and controversies involving the application or interpretation of tax law are known as: a. judicial authority. b. legislative authority. c. administrative authority. d. None of the above. 29. Post-1998 Temporary Regulations, which are often issued after-the-fact in response to a tax law change or an adverse judicial decision: a. have the full force and effect of law while in existence. b. are published simultaneously as Proposed Regulations. c. lapse after three years if not finalized. d. Two of the above. e. All of the above. 30. A Private Letter Ruling: a. is a District Director's response to a taxpayer's query regarding the tax consequences of a specific transaction or event. b. is a response to a specific taxpayer's request for an official IRS interpretation of a tax law provision as applied to the taxpayer's given fact situation. c. is issued in response to a question that arises during an audit. d. None of the above.