Definition: 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.
Input: Question: Find smallest prime number is:

 Option A: 13

 Option B: 21

 Option C: 14

 Option D: 18

 Option E: 42

Option A