Forget your condescending "Hint"
You are, by choice, a nobody.
You are addressing acknowledge Mathematicians.
If you believe you know the correct answer then spell out your reasons and give the answer, as you see it, in full.
Or if you are incapable of doing that then state why you believe a different answer is correct.
Like you could day. "The answer that the teacher gave me is .... but i do not know how she got it."