What you have given here are not supposed to be questions, but rather statements of indirect speech. A. He asked me which one was correct. B. He asked me which country I was from. C. He asked me who I was.
I am sorry. Yes, you are right those were statements not questions. BUT that's not the point I am trying to get. My grammar book says,'If the original question begins what, which,, or who followed by be+complement, we can put the complement before or after be in the report'. Which means the both forms are correct. Like: A. I asked who the winner was. And I asked who was the winner. B. He