The correct answer is D) Relative Deprivation Theory.
The theory that people join social movements because they feel deprived relative to other people or groups with whom they identify was the Relative Deprivation Theory.
The theory refers to the lack of resources to have a decent life, such as having property, a permanent and decent income, and the possibility to have extra money to invest or buying other things. There are societies that lack all of these and think that is a permanent condition that is difficult to change. The theory also implies the lack of some sights and the equality people wish in society.