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.

[EX Q]: Question: The purchase price of an article is $48. In order to include 5% of cost for overhead and to provide $12 of net profit, the markup should be

 Option A: 15%

 Option B: 25%

 Option C: 30%

 Option D: 40%

 Option E: 45%
[EX A]: Option C

[EX Q]: Question: In an electric circuit, two resistors with resistances x and y are connected in parallel. If R is the combined resistance of these two resistors, then the reciprocal of R is equal to the sum of the reciprocals of x and y. What is R if x is 5 Ohms and y is 7 Ohms?

 Option A: 3/5

 Option B: 1/7

 Option C: 12/35

 Option D: 31/12

 Option E: 35/12
[EX A]: Option E

[EX Q]: Question: The number 181 can be written as sum of the squares of 2 different positive integers. What is the difference of these 2 different integers?

 Option A: 3

 Option B: 2

 Option C: 1

 Option D: 4

 Option E: 5
[EX A]:
Option C