Analyzing the board, I noticed that in the bottom row (row 5) the opponent already has tokens in columns 3, 4, and 5. This creates a potential opportunity for the opponent to win by dropping their token in column 6 on their next turn, which would complete a row of four horizontally. By placing an O in column 6 now, I will block that immediate threat. Thus, the best move is to drop the piece in column 6 to deny the opponent a winning move while also waiting to set up my own future threats.