When a single political party runs all the affairs of government and limits the actions and freedoms of the people, the government is most likely a (an)

The correct answer is an oligarchy

An oligarchy is a system in which a minority rules over a majority. In this case, ti would be the single political party. A historical example of this would be Sparta where a tiny minority of the population, the Spartans, ruled over the majority of the population, which was the enslaved enemies and slaves in general who weren't from wars.