Final answer:
Temporary Decisions is not an administrative source of the tax law. Administrative sources of tax law are guidance and interpretations from the IRS and Treasury, and Temporary Decisions is not a standard term used to describe these sources.
Step-by-step explanation:
The question asks which of the following is not an administrative source of tax law. An administrative source of tax law refers to the guidance and interpretations provided by the Internal Revenue Service (IRS) and the Department of the Treasury to help in understanding and applying the laws enacted by Congress. The options presented are various forms of IRS and Treasury documents. Technical Advice Memoranda, Revenue Procedures, Actions on Decisions, and General Counsel Memoranda are all administrative sources of tax law. These documents provide the IRS's interpretation of tax law and guidance on procedural aspects. However, 'b. Temporary Decisions' is not typically recognized as a standard administrative source of tax law, like the others listed. Therefore, (b) Temporary Decisions is not an administrative source of the tax law.