Four charges $$Q_1, Q_2, Q_3$$ and $$Q_4$$ of same magnitude are fixed along the x axis at x = −2a, −a, +a and +2a, respectively. A positive charge q is placed on the positive y axis at a distance b > 0. Four options of the signs of these charges are given in List I. The direction of the forces on the charge q is given in List II. Match List I with List II and select the correct answer using the code given below the lists.