选择题
2015 AMC 8 Problem 11: Mathland License Plate
In Mathland, all automobile license plates have four symbols. The first must be a vowel, the second and third must be two different letters among the 21 non-vowels, and the fourth must be a digit. If the symbols are chosen at random subject to these conditions, what is the probability that the plate will read AMC8?
2015 AMC 8 第 11 题：Mathland 车牌
在 Mathland 中，所有汽车牌照都有四个符号。第一个必须是元音，第二个和第三个必须是 21 个非元音中的两个不同字母，第四个必须是数字。如果在这些条件下随机选择符号，则车牌上显示 AMC8 的概率是多少
A.
1/22050
B.
1/21000
C.
1/10500
D.
1/2100
E.
1/1050