The correct answer is C. Social movement
Step-by-step explanation:
The term "social movement" is defined as an organization of individuals that aims at changing some aspects of society or resisting these, this includes changes in politics, culture or specific institutions. This concept differs from a social revolution because in social revolution changes are already occurring, also, it differs from riots as these are violent. According to this, if there is a large group of people that promote or resist social change they are mainly involved in a social movement as it is this type of movement the one that encourages changes in society usually through non-violent means.