After analyzing the board, no immediate winning move for O was found. I checked possible aggressive moves (such as column 3 that might extend our horizontal chain, or column 2 to build a diagonal) but none gave a clear immediate win and some could potentially open up the board for a counter by opponent. Meanwhile, dropping a piece in column 1 is safe as it does not enable an immediate win for the opponent and helps establish a future possibility. Thus, I choose column 1.