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: The ratio of a to b to c is 2 to 3 to 4, and a, b, c are positive integers. If the average (arithmetic mean) of the three numbers is 36, what is the value of a?

 Option A: 21

 Option B: 24

 Option C: 25

 Option D: 27

 Option E: 30
[A]: Option B


[Q]: Question: If -5 < x < 7 and -6 < y < 3, which of the following specifies all the possible values of xy?

 Option A: -42 < xy < 30

 Option B: -42 < xy < 24

 Option C: -28 < xy < 18

 Option D: -24 < xy < 21

 Option E: -24 < xy < 24
[A]: Option A


[Q]: Question: A 300 meter long train crosses a platform in 39 seconds while it crosses a signal pole in 18 seconds. What is the length of the platform?

 Option A: 238

 Option B: 777

 Option C: 350

 Option D: 377

 Option E: 267
[A]:
Option C