Final answer:
The Anti-Federalists argued that the proposed Constitution gave too much power to the national government at the expense of the states and lacked a bill of rights to protect individual freedoms.
Step-by-step explanation:
The main strategy employed by the group opposing the proposed Constitution was D) Claiming the Constitution lacked protection of individual rights and granted excessive power to the central government. The Anti-Federalists had significant concerns about the Constitution, articulating that it would create a government too reminiscent of the overcentralized British regime, stripping the states of their autonomy.
They feared that a strong national government would be run by the wealthy elite, disadvantaging ordinary citizens and often highlighted the failure of the Constitution to include a bill of rights to protect individual liberties.
Anti-Federalists like George Mason and Patrick Henry were instrumental in advocating against the ratification of the Constitution without a clear bill of rights. Through their efforts and the conditional ratification by several states, they ensured the eventual inclusion of the Bill of Rights to safeguard civil liberties.
This historical debate reflects the tension between the need for a strong central government capable of unifying the nation and fears of the concentration of power that might infringe upon the rights and freedoms of individuals.