Final answer:
The Tenth Amendment is the constitutional provision that provides the least legal basis for a federal bureaucracy, as it reserves powers not delegated to the federal government to the states and the people.
Step-by-step explanation:
The constitutional provision that provides the least legal basis for a federal bureaucracy is d) The Tenth Amendment. This amendment states that the powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people. It sets the principle of federalism by reserving certain powers to the states and the people, limiting the scope of federal authority.
The Necessary and Proper Clause (a), the Supremacy Clause (b), and the Commerce Clause (c) all provide a substantial legal basis for the expansion and exercise of federal powers. The Necessary and Proper Clause allows Congress to enact legislation deemed necessary to execute its enumerated powers, the Supremacy Clause establishes federal law as the supreme law of the land in case of conflict with state laws, and the Commerce Clause allows Congress to regulate interstate commerce. These clauses have historically been used to justify the creation and expansion of federal agencies and regulations.