In a family, there are three sons: X, Y, and Z. X is the eldest son and Y is the youngest. Z is the only son who is married. If Z has two daughters, what is the relationship of Y to Z's daughters?
In a family of five members A, B, C, D, and E, A is the father of B. C is the mother of B. D is the brother of B. E is the sister of B. What is the relationship between C and D?