A bag of incense money was lost in the monastery. The abbot found three young monks, A, B and C, to inquire. The three men stated one by one, and A said, I didn't steal it. B said, A stole it. C said, I didn't steal it. D, who was on the side, learned the truth and commented, only one of you stole it, and only one of you was right.
Which one of them stole the incense money?
C