Answer: C. Group polarization.
Explanation: Group polarization can be explained as a collective behavior exhibited by a group such that a group of individuals are collectively inclined to employing an extreme or excessive attitude, action or behavior towards a particular subject than the original attitude, action or behavior of the individual member of such group.
The extremism in the action or attitude caused by group polarization may be in the form of the degree of being cautious or otherwise.
Group polarization holds that group actions is driven by how an individual's initial attitude has been strengthened after a group deliberation and determines the extremism in action exhibited by the group.