The last description makes the most sense, as to how the wording "mob" and "populace" imply them as behaving as group. Called social group psychology, many people "join the crowd" when it comes to supporting or opposing certain events, causes, or acts.
The main reason Harrison Bergeron is considered a threat in the eponymously titled short story is that he is able to rip off of his handicaps and make himself the self-proclaimed "Emperor," thereby removing control of the authoritarian regime that needs all of its citizens to weaken themselves and obey government commands.
The Answer is C - struggle between realistic and supernatural elements