Iqbal dealt some cards to Mushtaq and himself from a pack of playing cards and laid the rest aside. Iqbal then said to Mushtaq, “If you give me a certain number of your cards, I will have four times as many cards as you have. If I give you the same number of cards, I will have thrice as many cards as you.” How many cards did Iqbal have? (a) 9     (b) 12     (c) 31     (d) 35     (e) None of these