Yes, I should be more specific about 2.

So let's say the following are the first three questions you ask and their answers -

Q1. Do you think A is true? A. Yes. Q2. Do you think A=>B is true? A. Yes. Q3. Do you think B is true? A. No.

At this point, will you conclude that the person you are talking to is not rational? Or will you first want to ask him the following question.

Q4. Do you believe in Modus Ponens?

or in other words,

Q4. Do you think that if A and A=>B are both true then B should also be true?

If you think you should ask this question before deciding whether the person is rational or not, then why stop here? You should continue and ask him the following question as well.

Q5. Do you think that if you believe in Modus Ponens and if you also think that A and A=>B are true, then you should also believe that B is true as well?

And I can go on and on...

So the point is, if you think asking all these questions is necessary to decide whether the person is rational or not, then in effect any given person can have any arbitrary set of beliefs and he can still claim to be rational by adding a few extra beliefs to his belief system that say the n^th level of "Modus Ponens is wrong" for some suitably chosen n.