Answering negative sentences

[Nightright]

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 aren´t.

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.

[GoesStation]

I am an English learner and have a question about to the following American-English conversation. Will , so can a native American-English S speaker please help me?

Bryan: But they are not the same then.
Cathy: No they aren´t.

The "no" confuses me. So I ask myself what Cathy wants 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.

The answer is b).

[Tarheel]

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 aren´t.

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.

Cathy is expressing agreement (b)..

[Tarheel]

Say:

I have a question about the following American English conversation.

[Tdol]

a) That's wrong. In my opinion they are the same.

Yes, they are could supply this meaning.

[Nightright]

Hello and thank you for your answers and help.

Yes, they are could supply this meaning.

This is confusing me now. While "Goesstation" and "Tarheel" said Cathy agrees with Bryans statement "they are not the same" you say she disagrees and thinks they are the same?

[MikeNewYork]

That is not what Tdol said. He said that his response agrees with answer A.

[Nightright]

Bryan: But they are not the same then.
Cathy: No they aren´t.

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.

Well I'm confused now. Goesstation and Tarheel say it's B and Tdol A, but I'm realy confused now what's more logical in American English.

[GoesStation]

Bryan: But they are not the same then.
Cathy: No they aren´t.

Cathy is agreeing with Bryan. She could also agree with a statement like "no, this one is bigger than that one." If she wanted to contradict the speaker, she'd say "yes they are."

I agree, English makes this confusing. French is more logical in this area, at least: you use oui for the two concurring statements and si to contradict the assertion.

[Nightright]

So all in all the right meaning is:

Bryan: But they are not the same then.
Cathy: No [I agree], they aren´t [the same].

Correct?