And who is winning now anyway?

A game almost identical with tic tac toe is played on an $m\times m$ grid between players A and B.

Like in the classical game the winner is the one who can place 5 Os or Xs but this just on columns or rows diagonals not being included.

If A starts the game, and both players play optimally which of the following statements must be true?

Note that the players win just for consecutive signs on a column or a row and diagonals are not included.