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.

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
Option D

Question: P alone can complete a piece of work in 14 days. Work done by Q alone in one day is equal to one-third of the work done by P alone in one day. In how many days can the work be completed if P and Q work together?

 Option A: 6 (1/4

 Option B: 21/2 days

 Option C: 7 (3/4

 Option D: 8/5 days

 Option E: 9 (3/4
Option B

Question: The probability that a computer company will get a computer hardware contract is 4/5 and the probability that it will not get a software contract is 3/5. If the probability of getting at least one contract is 5/6, what is the probability that it will get both the contracts?

 Option A: 7/20

 Option B: 9/25

 Option C: 11/30

 Option D: 13/35

 Option E: 17/40

Option C