No, the awnser is A, 4:7. Because we know she has 4 red marbles and 7 blue marbles, so it is asking a ratio to red marbles, (4) to blue marbles, (7) so the correct awnser is 4:7. It is not C because they didn't ask for red marbles to total marbles if he did, it would be red marbles, (4) to total, 4+7+9 which equals 20. So it is not C because it would be 4:20.