instruction:
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:
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
answer:
Option D


question:
Question: Sum of 19 odd numbers is?

 Option A: 341

 Option B: 351

 Option C: 361

 Option D: 371

 Option E: 381
answer:
Option C


question:
Question: If the area of a circle decreases by 30%, then the radius of a circle decreases by

 Option A: 20%

 Option B: 16%

 Option C: 36%

 Option D: 64%

 Option E: None of these
answer:

Option B