Which choice best explains the meaning of the proofreading symbol in red?

I would need more details in order to answer this question. 

Ithink the answer going to be 5. i think. i hope my answer going to you. because i feel number five is the best answer.

In 2081, everyone is equal not only in the eyes of the law but in every way; nobody is smarter, more athletic, better looking, etc. than anyone else. hazel is of average intelligence, which means she can't think about anything except in short bursts, and george has an intelligence way above normal.