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: Consider Input: Question: (3x + 1) (2x - 5) = ax^2 + kx + n . What is the value of a - n + k ?

Option A: 5

Option B: 8

Option C: 9

Option D: 14

Option E: 11

Output: Option D

Input: Consider Input: Question: A man can do a piece of work in 5 days, but with the help of his son he can do it in 3 days. In what time can the son do it alone ?

Option A: 13/2

Option B: 19/2

Option C: 21/2

Option D: 15/2

Option E: None

Output: Option C

Input: Consider Input: Question: Each child has 2 pencils and 13 Skittles. If there are 15 children, how many pencils are there in total?

Option A: 30

Option B: 12

Option C: 18

Option D: 22

Option E: 08
Output: Option A