The correct answer would be "el libro mío" or you can also say "mi libro" which mean that that book belongs to you.
"el libro mi" --> mi is not place in the correct place so as I said before it would be place before the noun.
"mi el libro" again the position of "mi" s incorrect and "mio libro" has no sense bacause of the meaning of words. "this book is mine" "el libro es mio"
