I need to place my O at the bottom-left position (2,0) to block my opponent's diagonal threat. Currently, X has positions at (0,2) and (1,1), which creates a diagonal threat that would allow them to win if they place their next X at (2,0). By placing my O there, I not only prevent their immediate win but also start forming a potential column win along the left side, as I already have an O at the top-left (0,0). This defensive move is critical while also setting up a potential winning strategy for myself along the left column.