Task: Question Answering
Input (English): Problem: bag a contains red , white and blue marbles such that the red to white marble ratio is 1 : 3 and the white to blue marble ratio is 2 : 3 . bag b contains red and white marbles in the ratio of 1 : 4 . together , the two bags contain 28 white marbles . how many red marbles could be in bag a ? 
Options: a ) 1 , b ) 3 , c ) 4 , d ) 6 , e ) 7
Output (English): c