All of the citizens of a country have a six-character or seven-character national identification code that is created using the 26 letters of the alphabet and the 10 digits from 0 to 9. What is the maximum number of citizens who can be designated with these codes?  Choose the most appropriate option
A) 36^13
B) 35(36^7)
C) 37(36^6)
D) 35(36^6)
E) 37(36^7)
The number of possible 6-digit codes is 36^6.   The number of possible 7-digit codes is 36^7.   The total sum is 36^6 + 36^7 = 36^6(1+36) = 37(36^6)   The answer is 37(36^6).
<result>C</result>
All of the citizens of a country have a six-character or seven-character national identification code that is created using the 26 letters of the alphabet and the 10 digits from 0 to 9. What is the maximum number of citizens who can be designated with these codes?