You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.

Question: The least number of complete years in which a sum of money put out at 20% C.I. will be more than doubled is?

 Option A: 3

 Option B: 4

 Option C: 9

 Option D: 3

 Option E: 5
Option B

Question: 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?

 Option A: 36^13

 Option B: 35(36^7

 Option C: 37(36^6

 Option D: 35(36^6

 Option E: 37(36^7
Option C

Question: The cash difference between the selling prices of an article at a profit of 4% and 6% is Rs. 3. The ratio of the two selling prices is:

 Option A: 51:52

 Option B: 52:53

 Option C: 51:53

 Option D: 52:55

 Option E: 53:54

Option B