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 greatest common factor of 16 and the positive integer n is 4, and the greatest common factor of n and 45 is 3. Which of the following could be the greatest common factor of n and 210?

 Option A: 3

 Option B: 14

 Option C: 30

 Option D: 42

 Option E: 70
[A]: Option D


[Q]: Question: In a class of 40 students, 10 did not opt for math. 15 did not opt for science and 2 did not opt for either. How many students of the class opted for both math and science?

 Option A: 13

 Option B: 15

 Option C: 7

 Option D: 17

 Option E: 18
[A]: Option C


[Q]: Question: A certain animal in the zoo has consumed 39 pounds of food in six days. If it continues to eat at the same rate, in how many more days will its total consumption be 156 pounds?

 Option A: 18

 Option B: 7

 Option C: 12

 Option D: 9

 Option E: none of the above
[A]:
Option A