Read the excerpt from part 2 of "Flowers for Algernon."

Suddenly, I was furious at myself and all those who were smirking at him. I jumped up and shouted, "Shut up! Leave him alone! It's not his fault he can't understand! He can't help what he is! But for God's sake . . . he's still a human being!"

Based on this excerpt, how is Charlie changing as a person?

He is growing meaner.
He is gaining more knowledge.
He is becoming more sensitive.
He is losing his intelligence.