1.  Questions : How is X related to Y ? 
Statements :
 
I.  Y and Z are children of D who is wife of X.
II. R's sister X is married to Y's father.

A. I. alone is sufficient while II alone is not sufficient.
B. II. alone is sufficient while I alone is not sufficient.
C. Either I or II is sufficient is sufficient.
D. Neither I nor Ii is sufficient.
E. Both I and II are sufficient.

Answer: Option C

Explanation:

Form I, we conclude that Y is the child of D who is wife X i. e. X is Y's father. From II, X is married to Y's father. This implies that X is Y's mother.