King or Queen rules the country. Monarchs come to power through their family line. Monarchs held all power in historical times. In modern times, power is usually shared with other parts of government.
One leader has absolute power over citizens' lives. The dictator has all control over Constitution, if there is one. Other parts of government may exist but they are required to always do what the dictator tells them to. Citizens are not represented.
Citizens elect their leaders to represent their rights and interests in government. The elected leaders do the daily work for country: Consider and solve issues, pass laws, and anything to keep the country running. Citizens hold ultimate power through voting.
Oligarchy is a Greek word meaning "rule by a few". A small group of people hold all of the power. This sometimes means only a certain group has political rights. For example, only one political or social class can participate in politics.
A government recognizing God or a higher being as ultimate authority. Religious laws are used to settle disputes and rule people. Modern Theocracy is often found in countries where population has strong religious beliefs.
Nobody has control or everyone does. It describes the human state of existence before government developed. Anarchists today believe people should be allowed to freely associate without being subject to a nation or government. No country's government is an anarchy.