In Which of the Following Situations Is "Spontaneous Collective Behavior

In which of the following situations is "spontaneous collective behavior" most likely to occur?

A) a rally sponsored by a hierarchical organization
B) a protest march without any set leader, initiated by a loose affiliation of volunteers
C) a political campaign event in which professional managers decide the order of speakers and activities
D) a wedding with a clearly defined series of activities, organized by an experienced wedding planner