We would like to design a data structure to maintain the records of a group of people. Besides insertion and searching, the data structure should also support the two operations: Find-Closest and Find-Furthest, which find the two people closest and furthest in age, respectively. We would like all operations to take O(log n) time for any group of n people. Suppose that we use a Red-Black BST:

1. Which field should be used as the key, and what additional information, if any, needs to be stored at each node to support the required operations?

2. Show how the operations Find-Closest and Find-Furthest can be implemented to take O(log n) time.