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: If the line L passes through the point (3,n) and (n,3), where n is not equal to 3, which of the following must be true?
1. Line L must passes through the first quadrant
2. Line L does pass the origin
3..The slope of L is negative

 Option A: I only

 Option B: II only

 Option C: III only

 Option D: I and II

 Option E: II and III
[EX A]: Option C

[EX Q]: Question: A train covers a distance of 12 km in 10 min. If it takes 10 sec to pass a telegraph post, then the length of the train is?

 Option A: 100

 Option B: 110

 Option C: 200

 Option D: 130

 Option E: 140
[EX A]: Option C

[EX Q]: Question: In February Wilson’s earnings were 40 percent of his family’s total income. In March Wilson earned 25 percent less than in February. If the rest of his family’s income was the same in both months, then, in March, Wilson’s earnings were approximately what percent W of his family’s total income?

 Option A:  15%

 Option B:  17%

 Option C:  24%

 Option D:  30%

 Option E:  33%
[EX A]:
Option E