Answer:
d. When people join a crowd, they lose their individuality and become part of something like a collective mind.
Step-by-step explanation:
According to the Classical Theory of crowd behaviour the correct answer is d. When people join a crowd, they lose their individuality and become part of something like a collective mind. Classical Theory states that the minds of those peoples integrating a crowd or group of people tend to "merge" their way of thinking into a single one. This way of social thinking fosters anonymity and may generate emotions. There are other valid theories such as Contagion Theory, Convergence Theory and Group Mind Theory among others.