I'm choosing column 3 because it creates a vertical stack of two O pieces (in rows 4 and 5) and forms a diagonal connection with my existing O in column 4, row 3. This gives me two different sequences of two pieces - one vertical and one diagonal. The move doesn't give my opponent any immediate threats to counter, and by playing in a central column, I maintain flexibility for future moves. None of the other columns offer me an immediate connect-four opportunity or require me to block my opponent from making one, so this strategic position-building move is best.