Analyzing the board, the opponent has a potential diagonal threat with their X pieces at (5,1) and (4,2), where placing at (3,3) could set up a future win. By dropping our O into column 3, which will fall to row 3, we block that threat while also building a horizontal line (with O’s already at row3 col1 and col2) for future opportunities. Thus, column 3 is the best move.