The correct response to analyze why the Anti-Federalists feared a large national government is:
They feared that the national government would consolidate all the power leaving the states with no power at all.
Anti-Federalists were concerned that a strong national government would undermine state authority and individual liberties. They believed that a central government could become tyrannical, with too much power concentrated at the national level, thereby threatening personal freedoms and the rights of states to govern themselves. This fear reflected their commitment to preserving the autonomy of states and the belief that local governments could better represent the interests and needs of their communities.