40. In a queue, Mr. X is fourteenth from the front and Mr. Y is seventeenth from the end, while Mr. Z is exactly in between Mr.X and Mr.Y. If Mr.X is ahead of Mr. Y and there are 48 persons in the queue, how many persons are there between Mr. X and Mr. Z? (a) 6 (b) 7 (c) 8 (d) 9