I am an English learner and have a question to the following American-English conversation, so can a native American-English Speaker please help me?
Bryan: But they are not the same then.
Cathy: No they arenīt.
The "no" confuses me. So I ask myself what Cathy want's to say with her answer:
a) That's wrong. In my opinion they are the same.
b) I agree, They are not the same.

Student or Learner