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: If 3^x*4^y = 1,594,323 and x – y = 13, then x = ?

 Option A: 10

 Option B: 11

 Option C: 12

 Option D: 13

 Option E: 14
Option D

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
Option C

Question: (1.00001)(0.99999) - (1.00005)(0.99995) =

 Option A: 0

 Option B: 10^-10

 Option C: 3(10^-10

 Option D: 10^-5

 Option E: 24(10^-10

Option E