In a family, there are four members: A, B, C, and D. A is married to B, and they have two children, C and D. If C is older than D, who is the youngest member of the family?
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 if A + C - B?
In a coded relation, if P × Q means P is the mother of Q, P ÷ Q means P is the father of Q, and P + Q means P is the son of Q, what is the relationship of R if P × R ÷ Q?