If A + B means A is the brother of B, and B - C means B is the sister of C, what is the relationship between A and C?

C. COUSIN

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

C. CHILD

If M × N means M is the mother of N, and N + O means N is the son of O, what is the relationship between M and O?

D. MOTHER-IN-LAW

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

A. NIECE

If N is the daughter of O and P is the son of O, what is the relationship of N to P?

A. SISTER