As an undergrad they loved me , and respected me because I was so full of enthusiasm and energy . Then I go to graduate school , at their request and constant insisting , and then it 's " no no no , stop all of that nonsense about helping or changing the world . here we just inform ourselves about things .

Question: Why would people tell the writer to stop their nonsense about helping people or changing the world ?
Answer: Because the undergrats respect the writer .Because the undergrads love the writer .None of the above choices .Because the people are jaded and do n't believe the writer can make a difference .