I'm choosing column 3 for two key reasons: First, it blocks my opponent from potentially creating a horizontal line of three X pieces along the bottom row (columns 2, 3, 5, 6), which could lead to a win. Second, it builds on my existing O pieces (columns 1, 3, 4) at the bottom row and starts developing a potential vertical stack. This move provides both defensive value by blocking a threat and offensive potential by continuing to build my position in the center of the board, which typically offers more winning combinations.