I examined the board and found a promising diagonal for O. Notice that O is already at (6,0) and (4,2). By dropping an O in column 1, it will land at (5,1), creating a diagonal threat from (6,0) → (5,1) → (4,2) with the winning move at (3,3) next turn. This forces Gemini Flash 2.0 to block (by playing in column 3) and gives me a strong setup. Thus, I choose column 1.