Please note that the best interpretation and the only interpretation are two different things. For something to be the best there has to be more than one. It is pointless to talk about "best" if there is only one.

Interested in Language
Two things. Please don't use chatlish. Every single contraction should have an apostrophe. "I'm" is the contraction for "I am". I don't see why you why you still have a question about this one. (I'm not sure why this thread should continue.)
Please note that the best interpretation and the only interpretation are two different things. For something to be the best there has to be more than one. It is pointless to talk about "best" if there is only one.
Yes. Please don't ask us to clarify this clear answer any more.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.
Okay thank you. :) But what you mean with parentheses? Which part of the question is not needed?
Parentheses are brackets. You should have written "... the only interpretation is that both Bryan and Cathy agree ...".
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.
Ah Okay, i searched for the stylistic device. Then thank you for your friendly answers. :) It helped me a lot. I am somehow a little bit unsure, if this all fits for the whole conversation. I just got nervous the conversation before changed the meaning:
Bryan: Is that an old photo of your friend?
Cathy: No, I don't think so.
Bryan: Okay, I always need to think about that person on the picture, who I thought was your friend. But they are not the same then.
Cathy: No they aren't.
If you see the whole conversation, is Cathys last answer "No they aren't." = "No, I agree, they are not the same."?