The correct answer is (C):
Given, ratio of the scores of Amal and Bimal is 11 : 14.
Let 11x and 14x be the scores of Amal and Bimal.
Let a be the score which is increased.
⇒ 11x+a/14x+a = 47/56
616x+56a = 658x + 47a
9a = 42x
a = 42x/9
Required ratio = (14x+42x/9):14x
= (1+1/3):1
= 4:3