Answer:
Contagion.
Explanation:
Contagion effect may be defined as a kind of the social influence. This refers to the certain behavior that are exhibited by one person and can be copied by other individual.
The individual might copy the original actor that has been exposed by the media or by the crowd. This explain the undesirable and unexpected aspects of the different behavior of the people in the crowd. This can also be included in the collective human behavior.
Thus, the correct answer is option (b).
