|A) Grandfather||B) Father|
|C) Uncle||D) Brother|
C is the daughter-in-law of A who is the grandmother of' F means C is the mother of F But F is the son of B.
So. B is C's husband. But C, the lawyer. is married to the Doctor So. B is the Doctor. F, the Accountant, will be the non of B and C, E is the unmarried Engineer
So, the other mamed couple can be that of grandmother of Fie A and 0 But D. the Salesman, is married to the Lady Teacher.
So. D, the Salesman, is the grandfather of F, father of B and the husband of A, the Lady Teacher.
D is the grandfather of F.