"ask" "ask for" or "ask about", which to use

Question

We are discussing the usage of "only" in another post ("only has" vs. "has only", when to use which?).

I am asking the reason why "only" could not be used as an adjective in my second example.

I guess I could say

I am asking the reason ...

I am asking for the reason ...

I am asking about the reason ...

I want to show my politeness. I am not sure which one of those is appropriate.

Could someone please give a hint?

Answer 1

I am asking the reason, (you are looking for the reason).

I am asking for the reason, (you demand or request for the reason).

I am asking about the reason, (you are asking for the information about the reason).