Correct answer choice is:
A. They had differing ideas about who could vote.
Every state had its own government and constitutions, with its own laws. Every state has the power to decide who can vote, for example, among different things. The states were united into one all-embracing state, ruled by the ‘federal’ government. The USA, like Canada, may be a ‘federal’ state. It's created from smaller freelanced units that mix to make a bigger whole.