I analyzed the board and noticed that your O pieces at column 1 are already two in a row (at row5 and row4). By dropping an O into column 1, your piece lands at row3, forming three in a vertical column. This creates an immediate threat because if o1 (playing as X) ignores it, you can drop another O in column 1 on your next turn to win via a vertical connect-4. This move also forces your opponent to block your winning move rather than pursue their own strategy, making it the best choice.