In February 006, two sections X and Y of a certain highway entered the bidding stage, and there were four units of A. B, C, and the factory. Xiao Wang believed that: "Either Jia won the bid or B won the bid. " Xiao Li believed : "Both A and C can win the bid. " Xiao Zhou said: "Can't say if Ding wins the bid, then C wins. " Xiaoma believes: "Ding cannot win the bid. ". If only one of the four people is wrong, which two units cannot win the bid? ['Ding, C.', 'A. B.', 'B, D.', 'A. C.']