Which of the following events is a example of a revolution?
a. a group of protesters hang posters that say the current president is not good for their country.
b. a group of people overthrow the monarch of their country and set up a democratic government.
c. a group of politicians vote to change the frequency of elections in their country.
d. a group of businessmen lobby to change the regulation on business in their country.

The correct answer is - b. A group of people overthrow the monarch of their country and set up a democratic government.

When a big mass of people gather and they have a goal of overthrowing the monarch because they are not content of their living conditions under his/hers rule, and manage to do it in order to set a new government that will be democratic and will be serving the interests of the people, can be considered as a revolution. A nice example for this, but also a brutal one, is the Romania's case with the overthrowing of Ceausescu (who was murdered) in order to set up a democratic system and not allow the dictatorship to continue.