Subject: mathqa
Question: a bag contains 12 red marbles . if someone were to remove 2 marbles from the bag , one at a time , and replace the first marble after it was removed , the probability that neither marble would be red is 49 / 64 . how many marbles are in the bag ?
Option: 
A: 84
B: 24
C: 96
D: 48
Answer: C