The primary concern of the Antifederalists was that the Constitution granted the president too much power, particularly in relation to the potential for tyranny. Among the options provided, the one that relates to their concerns about individual rights and the concentration of power is:
military power, as commander-in-chief.
They feared that the president's military authority could lead to the oppression of citizens. This concern contributed to their calls for a Bill of Rights to protect individual liberties against potential government overreach.