They might have not met someone who is a teenager automatically they just go to that stereotypical teenager
General Zaroff sees pain and suffering as something pleasurable. He believes that he is a god and that he can surpass anything. He is rich and is one of the most respectable people in the military. He sees hunting as an adrenaline rush. He sought to kill the bigger games just to feed the rush in his system. He will kill animals or humans, he can't tell between animals or humans due to his hunger for hunting.
The answer is give the letter to whoever answers the bell.