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: A can work three times as fast as B. Together they can finish a job in 12 days. In how many days can A complete the job alone?

 Option A: 14

 Option B: 16

 Option C: 18

 Option D: 20

 Option E: 22
Output:
Option B