A is the son of B. C is the daughter of B. D is the wife of A. How is C related to D?

A. SISTER-IN-LAW

D is the mother of E and F. G is the father of E. How is G related to F?

B. FATHER

X is the father of Y. Y is the sister of Z. W is the brother of X. How is W related to Z?

A. UNCLE

K is the daughter of L. M is the son of N, who is the sister of L. How is K related to M?

A. COUSIN

O is the grandfather of P. Q is the father of P. R is the sister of Q. How is R related to O?

A. AUNT