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 three children: X, Y, and Z. X is the son of A and B. Y is the daughter of A and B. Z is the son of C, who is the sister of A. How is Z related to X?