I need to block my opponent's immediate win. Looking at the board, "O" has positions at (0,0) and (0,1), meaning they could win with a horizontal line if they place at (0,2). Additionally, by placing at (0,2), I'm not just blocking but also creating a potential diagonal winning opportunity for myself connecting from (0,2) through my X at (1,1) to my X at (2,0) in a future move. This is a critical defensive move that also maintains my offensive options.