Question 2. For this question, you may assume the following class definition for an integer Binary Search Tree (BST) class: public class IntBSTNode protected int key; protected IntBSTNode left, right public IntBSTNode (int e t key e; left right null public class IntBST protected IntBSTNode root public Int BSTC) root null You are given the method SumofNodes() of the IntBST class which returns the sum of the key values of a given BST. It uses an auxiliary function which takes the root of the given tree and returns the sum. Implement the auxiliary function SumofNodes (root) using recursion public int Sumof Nodes C) f return Sumof Nodes (root); private int Sumof Nodes (IntBSTNode root) b. Consider the following implementation of a tree traversal algorithm which creates a string of the contents of a BST: private String mystery(IntBSTNode root) if (root null) return if ((root .leff null) && (roots .ri. null) ght return root.key else return mystery (root left) mystery Groot.right); Apply this algorithm to the tree given below starting with the root of the tree and show the resulting string. Page 3