P is the brother of Q and R. S is R's mother. T is P's father.
Which of the following statements cannot be definitely true ?

E. Q IS T'S SON.

All the six members of a family A, B, C, D, E and F are travelling together. B is the son of C but C is not the mother of B, A and C are a married couple. E is the brother of C. D is the daughter of A. F is the brother of B. How many children does A have ?

C. THREE

A man and his wife have three sons, and every of the sons has a sister. How many are there in the family ?

C. 6

A, B, C, D, E, F and G are members of a family consisting of four adults and three children, two of whom, F and G are girls. A and D are brothers and A is a doctor. E is an engineer married to one of the brothers and has two children. B is married to D and G is their child.
Who is C ?

A. A'S SON

E is the son of A.
D is the son of B.
E is married to C.
C is B's daughter.
How is D related to E ?

D. BROTHER-IN-LAW