Which country most likely has a two-party political system

Most likely is The United States Of America.

A two-party political system is where there are two political parties that control the government. Lets take the United States for example, there are more than two political parties that are active, however, only two control the majority of the Government. The parties are Democrats and Republicans, each have their own views on how the Country should progress and they have controlled Congress for some time.

Your answer would be the United States.