I'm choosing column 2 because it blocks a potential horizontal threat by my opponent. If I don't place my piece here, my opponent could place an X in column 2 on their next turn, which would create a horizontal line of 3 X's (connecting with the X's in columns 3 and 4) with an open space at column 5. This would create a two-way threat that would be difficult to defend. Additionally, placing my piece in column 2 starts building my own vertical presence in that column, where I already have a piece at the bottom row.