The answer is C-49
Here's why: We know the number has to divide into 7 even parts, because we want 3/7 of it. Then we know we add 3 of those parts together, and we get 21. First we would divide 21 by 3, which is 7. Then we would see if 7 goes into 49 7 times, which it does! Therefore, the answer is C-49. Hope that helps!
