What did the Anti-Federalists fear about the US Constitution?

The Anti-Federalists were primarily concerned that the US Constitution, as proposed, would concentrate too much power in the hands of the federal government at the expense of the states. They believed that a strong central government could become tyrannical and undermined the power and autonomy that states held under the Articles of Confederation. Their apprehension was rooted in a desire to preserve local governance and prevent potential overreach by a distant national authority. They felt that the Constitution's lack of explicit protections for individual rights would exacerbate this issue, resulting in a government that might not be accountable to the people and could infringe upon their freedoms.

The other choices represent different concerns that were raised during the debate over the Constitution but did not capture the primary fears of the Anti-Federalists accurately. For instance, the concern about the establishment of a monarchy, while a historical reference, was less about the specific structure of government the Constitution proposed, and more about the fear of a powerful central government. The idea that it would provide too much power to the states or limit individual freedoms were not the main points of contention; rather, the Anti-Federalists focused on preserving state sovereignty and ensuring that the rights of individuals were explicitly protected.