If A + B means A is the sister of B, B - C means B is the brother of C, and C * D means C is the mother of D, what is the relationship of A to D?

A. AUNT

If P - Q means P is the mother of Q, Q + R means Q is the sister of R, and R * S means R is the father of S, what is the relationship of P to S?

A. GRANDMOTHER

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

If P is the grandmother of Q, and Q has a brother R, what is R's relation to P?

A. GRANDSON

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 to D if C + D and D - C are true?

A. C IS D'S BROTHER