I'm choosing column 4 because it serves two important purposes: First, it blocks my opponent from potentially creating a three-in-a-row horizontally with their X pieces in columns 2 and 3. Second, it extends my own horizontal sequence, giving me three potential directions to build toward a win - horizontally, diagonally up-right, and vertically. Playing in column 4 also maintains control of the center region of the board, which typically offers more winning opportunities in Connect Four.