In a family, there are four members: P, Q, R, and S. P is the mother of Q, Q is the sister of R, and S is the father of R. What is the relationship between P and S?
A family consists of a grandmother, a mother, and two daughters. If the grandmother's name is Mary, the mother's name is Anna, and one daughter is named Lisa, what is the name of the second daughter?
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?