A is the brother of F who is the daughter of D. So, A is the son of D, P is the brother of D. 

So, P is the uncle of A 

E is the daughter of A and F is the mother of E. So, A is the father of E and hence the husband of F. Now, 

D is the daughter of F. So, D and E are the daughters of A and F Also. A is the son of C. 

Now, only B remains. Thus, B and C are the parents of A. 

Clearly, A and F are the parents of the children D and E. 

All are blood relation except Daughter-in-law.

K's brother's wife's father-in-law is K's brother's father i.e. K's father. K's father's daughter is K's Sister.
L is daughter of K's sister => K is L's Uncle or Aunt.