1.  Question: How is X is related to Y ?
Statements:

I.  Y says, " I have only one brother".
II. X says, "I have only one sister"

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
D. Neither I nor II is sufficient
E. Both I and II are sufficient

Answer: Option D

Explanation:

The statements in I and II do not provide any clue regarding relation between X and Y.