In a family of four members A, B, C, and D, A is a doctor, B is a teacher, C is a lawyer, and D is a student. If A is married to B and they have two children, who is the parent of C?
In a family, there are four members: P, Q, R, and S. P is the father of Q, Q is the mother of R, and S is the sibling of R. What is the relationship between P and S?