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: If a committee of 2 people is to be selected from among 5 married couples so that the committee does not include two people who are married to each other, how many such committees are possible?

 Option A: 20

 Option B: 40

 Option C: 50

 Option D: 80

 Option E: 120
[A]: Option B


[Q]: Question: ♠n denotes the number obtained when n is rounded to the nearest tenth. For example ♠4.31 = 4.3
♠0.089 - ♠2.135 =

 Option A: 1.05

 Option B: 1.04

 Option C: -1.05

 Option D: -2

 Option E: -0.1
[A]:
Option D