Answer: It allows the reader to learn what Helen is thinking and feeling when she discovers language.
Explanation: In the passage it states, “and somehow the mystery of language was revealed to me.” The pov is from Helen, so it is not the first option. The second option we can rule out immediately I hope for obvious reason. And as the text stated, the third option would be correct because she now understood what language was since Annie showed her what water means in sign language.