The first alternative is correct (A).
The anti-Federalists defended the decentralization of power.
They were a group that worked on the founding of the US Constitution and actually advocated a Confederative system, which would be an association of sovereign states. However, they were defeated by the Federalists.
The anti-Federalists resisted the concentration of sovereign power in the hands of the Federative State, because it was against what the settlers fought in the Wars of Emancipation, defending, therefore, the autonomy of each state.