Task: Question Answering
Input (English): Problem: 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 36 / 49 . how many marbles are in the bag ? 
Options: a ) 24 , b ) 48 , c ) 84 , d ) 72 , e ) 80
Output (English): c