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

A. UNCLE

If K is the son of L and M is the sister of L, what is the relationship of M to K?

A. AUNT

If A is the brother of B and C is the sister of B, what is C to A?

A. SISTER

If M is the grandmother of N and O is the mother of N, what is O to M?

A. DAUGHTER

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

A. C IS THE SISTER OF B