Which of the following is not found in the United States Code?

Common law is not codified in the United States Code, which primarily contains statutory laws enacted by legislatures. Statutory law refers to laws that have been explicitly written and enacted by a legislative body, forming a structured and organized collection of legal statutes. Regulations, on the other hand, are rules made by executive branch agencies that interpret and implement statutory laws, and these can be found in the Code of Federal Regulations rather than the United States Code itself.

Constitutional law is derived from the U.S. Constitution and its interpretations, including judicial rulings, and while it influences statutory and regulatory frameworks, it is not codified in the same manner. Common law, which evolves from judicial decisions and legal precedents rather than statutes or regulations, embodies legal principles developed through court rulings over time. Since these principles are not formally written into a statutory code, they do not appear in the United States Code. This distinction clarifies why common law is the correct answer to the question.