I analyzed the board and looked at potential opportunities to build up a connect-four, as well as block potential future moves by the opponent. By dropping an O in column 2, it will settle in the next available row (row 4) in that column, setting up for a potential horizontal line with the existing O at (row 4, column 3) and creating possibilities for future diagonal or vertical connections. It doesn't expose us to immediate threats either, so I choose column 2.