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.

[Q]: Question: What sum of money will produce Rs.70 as simple interest in 4 years at 3 1/2 percent?

 Option A: 266

 Option B: 500

 Option C: 287

 Option D: 26

 Option E: 281
[A]: Option B


[Q]: Question: The average of first ten prime numbers which are odd is?

 Option A: 15.5

 Option B: 15.7

 Option C: 15.2

 Option D: 15.8

 Option E: 15.1
[A]: Option D


[Q]: Question: If 1/(x+1)+1/(x-1)=1/(x-1), what is the value of x?

 Option A: 2

 Option B: -2

 Option C: 1

 Option D: -1

 Option E: 5
[A]:
Option C