Final answer:
Revenue Letters and Revenue Rulings are second in administrative authoritative weight after regulations, making the answer A) Letters, Rulings.
Step-by-step explanation:
The question concerns the hierarchy of administrative authoritative weight within the context of U.S. tax policy and law. The correct answer is A) Letters, Rulings. These administrative pronouncements, such as Revenue Letters and Revenue Rulings, come second only to regulations in terms of authority. Regulations are formal rules issued by administrative agencies, operating under the executive branch, to implement legislation and enforce statutes. While these regulations carry significant authority, Revenue Letters and Revenue Rulings are used to interpret the tax law and provide guidance to taxpayers and tax professionals. They are considered less authoritative than regulations but more so than other informal guidance.