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: The ages of two friends is in the ratio of 6:5.If the sum of their ages is 66. Then after how many years will the ratio become 7:6?

 Option A: 5

 Option B: 6

 Option C: 8

 Option D: 9

 Option E: 10

Option B