How many persons are sitting between G and D?   

Wife of E sits second to the left of E. Mother of E sits on the immediate right of wife of E. Both E and wife of E faces same direction. Only two persons sit between mother of E and M. Persons sitting at the ends face opposite direction. So, from this case 1 and case 4 gets eliminated. G and wife of A are immediate neighbours of each other. G is the niece of E. D is married to J. A is the son-in-law of D. A and J are not immediate neighbours. J and M faces same direction. A and G face same direction. Immediate neighbours of E face opposite direction.