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 60?
Choose the correct choice:
A) 5	B) 8	C) 12	D) 15	E) 30
n includes the factors 2^2 (but not 2^3) and 3 (but not 3^2 or 5)   60 = 4*3*5   The GCF is 12.   The answer is 12.
<result>C</result>
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 60?