The correct answer is (B):
Let the number of marbles with Raju and Lalitha initially be 4x and 9x.
Let the number of marbles that Lalitha gave to Raju be y.
It has been given that (4x+y)/(9x-y) = 5/6
24x + 6y = 45x – 5y
11y = 21x
y/x = 21/11
Fraction of original marbles given to Raju by Lalitha = y/9x (As Lalitha had 9x marbles initially).
y/9x = 21/99
= 7/33.