All employees at Company W are assigned unique employee ID codes that consist of numbers and letters from the alphabet. If letters can be repeated within the same code but numbers cannot, which of the following must be true?
A.There are 2,600 possible different 3 digit codes consisting of 1 letter and 2 digits.
B.There are 60,840 possible different 4 digit codes consisting of 2 letters and 2 numbers.
C.There are 650 possible 2 digit codes consisting of 1 letter and 1 digit.
我的答案：
