请教各位大侠，对OG 49的疑问

tobeistodo

49. A milepost on the towpath read “21” on the side facing the hiker as she approached it and “23” on its back. She reasoned that the next milepost forward on the path would indicate that she was halfway between one end of the path and the other. However, the milepost one mile further on read “20” facing her and “24” behind.

Which of the following, if true would explain the discrepancy described above?

(A) The numbers on the next milepost had been reversed.

(B) The numbers on the mileposts indicate kilometers, not miles.

(C) The facing numbers indicate miles to the end of the path, not miles from the beginning.

(D) A milepost was missing between the two the hiker encountered.

(E) The mileposts had originally been put in place for the use of mountain bikers, not for hikers.

这题逻辑很清楚简单

21/23

next --- halfway          →                  22/22

＋

20/24

＝discrepancy

思路就是，在形成矛盾的二者之间搭桥，答案说C，我认为答案是D。我认为漏掉了一个22/22的里程碑。如果是选C，跟“下一个里程碑说明她跑了一半”，这个前提相矛盾了呀。