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.

ans: C

我明白为什么选C. 但是我觉得其实A也行。

对于A，我的理解是可以存在这种情况：本来上面是22，22，但是被修改以后变成了20，24。

这也同样解释了文中出现的矛盾呀----就是数字被改了呗。

og的解释我也有点看不明白：choice A can not be the explanation, because if the hiker's reasoning were correct, both numbers on the milepost would be 22.

盼解答，谢谢！：）