The opponent has three X's in a row, which could be a potential winning line. However, since there are no X's above the top X, it's likely that o3-mini - (low) will try to extend this line either horizontally or diagonally. To counter this and create future opportunities, I should aim to place my piece in a column where I can potentially create a line of 4 or limit o3-mini - (low)'s options. Given that column 3 is somewhat contested and the top row is empty, placing my O on either side of the contested area could limit o3-mini - (low)'s expansion and prepare for my next moves. Considering these factors, the best move seems to be placing my piece in one of the outer columns to limit the opponent's future moves and create possibilities for my own winning line.