Pointing to a boy in the photograph Reena said, "He is the only son of the only child of my grandfather." How Reena is related to that boy?

Brother of person's wife ? brother-in-law of the person. Hence, the son of lady's brother is brother-in-law of the person.

Therefore, the brother of the lady is the father-in-law of the person. Hence, the lady is the sister of the person's father-in-law.

Only the child of my father means 'Abhisek' himself. This means the girl is the daughter od Abhisek. Hence, Abhisek's wife is the mother of the girl.

I x C ? I is the sister of C

C + N ? C is the daughter of N

and N - J ? N is the brother of I.

Hence, I is niece of J.

K + Y ? K is the brother of Y

Y x I ? Y is the father of I

Hence, ? K is the uncle of I

and I - Z ? I is the sister of Z

Hence, ? I is the niece of K.

Q $ R ? Q is the father of R

R @ T ? R is the brother of T

Hence, ? Q is the father of T

T * M ? T is the daughter of M

Hence, ? M is the mother of T

Hence, M is the wife of Q.

Daughter of Abhijit's brother ? niece of Abhijit. Thus the granddaughter of the woman is Abhijit's niece.

Hence, the woman is the mother of Abhijit.

A and B are children of D.

From (1), C is the brother B and son of E.

Since, the sex of D and E are not known. Hence (1) is not sufficient to answer the question.

From (2). F is the mother of B. Hence, F is also the mother of A. Hence D is the father of A.

Thus, (2) is sufficient to answer the question.

The father of the boy's uncle ? the grandfather of the boy and daughter of the grandfather ? sister of father.

The man in the photograph is son of Anjali's grandfather's son i.e., the son of Anjali's father. Hence, the boy is the brother of Anjali.