Explanation:

B is brother of P. K is father of them. A is wife of P. N is daughter of P and A. N is son/daughter of P and A. T is married to N.
Now:: C is mother of D. L is sister-in-law of D and M is daughter of L.
Now there are two possibilities:
First — D is sister of A and L is wife of D’s and A’s brother. But C has only 1 daughter so A and D cant be both daughters. So this cancels out.
Second — D is sister of P. C is wife of K. Now L is sister-in-law of D and D is not married so L is daughter-in-law of C and K. Cannot be necessarily wife of B.
C can have more children, thus L can be wife of  any other person too other than B.