The example that BEST illustrates collective behavior is:
B. a crowd that gathers when a fight breaks out.
Here's why:
1. Collective behavior refers to the actions, thoughts, and feelings of a group of people who are together in a particular situation or environment.
2. In the scenario of a crowd gathering when a fight breaks out, individuals are influenced by the presence of others, and their behavior is not planned or organized in advance.
3. The crowd's actions are spontaneous and can involve a range of behaviors such as cheering, intervening, or simply observing the situation.
4. This example demonstrates how people in a group can react collectively to a stimulus or event without prior coordination, showcasing a classic case of collective behavior.