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: Find the equation of a line which passes through A(4, -1) and is parallel to x axis.

 Option A: y=-2

 Option B: y=3

 Option C: y=2

 Option D: y=-1

 Option E: y=0
[EX A]: Option D

[EX Q]: Question: On what dates of April, 2001 did Wednesday fall?

 Option A: 1st, 8th, 15th, 22nd, 29th

 Option B: 2nd, 9th, 16th, 23rd, 30th

 Option C: 3rd, 10th, 17th, 24th

 Option D: 4th, 11th, 18th, 25th

 Option E: None of these
[EX A]: Option D

[EX Q]: Question: If 2/3 of the air in a tank is removed with each stroke of a vacuum pump, how many strokes does it take before less than 1% of the original amount of air in the tank remains?

 Option A:  2

 Option B:  3

 Option C:  4

 Option D:  5

 Option E:  6
[EX A]:
Option D