According to one of the theories of social movements, social conflict arises when a social group feels that it is worse off than others around it. What is this theory known as?

The correct option is Theory of Relative Deprivation.

Relative deprivation is a key sociological concept and theory of social movements. It posits that social conflict and collective action arise when a specific social group perceives a discrepancy between their actual situation and their expectations, or when they feel they are disadvantaged compared to a reference group.

This feeling of being worse off in comparison to others leads to dissatisfaction, which can act as a catalyst for social movements as individuals mobilize to address the perceived inequality. Therefore, the theory explaining social conflict arising from a group feeling worse off than others around it is the Theory of Relative Deprivation.