M is the uncle of N. N is the daughter of O. How is O related to M?

B. SISTER

X is the father of Y. Y is married to Z. Z has a brother W. How is W related to X?

C. BROTHER-IN-LAW

A is the brother of B. C is the sister of A. How is C related to B?

A. SISTER

O is the grandmother of P. Q is the father of P. R is the brother of Q. How is O related to R?

B. MOTHER

P is the uncle of Q. Q is the daughter of R. R is the sister of P. How is R related to P?

A. SISTER