Final answer:
Massachusetts and Pennsylvania were the states most likely to favor congressional representation based on population due to their larger size and push for a stronger central government.
Step-by-step explanation:
The states most likely to favor representation in Congress based on population were Massachusetts and Pennsylvania. This is because, historically, larger states such as these sought a stronger central government with legislative representation proportionate to their population. Figures like George Washington, Alexander Hamilton, and James Madison from these populous states advocated for this system, as it would ensure that states with larger populations would have more representatives in Congress. This was opposed to the idea of equal representation regardless of population size, which was favored by smaller states like Delaware, New Jersey, Connecticut, and Maryland.