QUESTION 22 A simple implementation of a node for a binary tree is shown below. For this question, you are to implement a method called isBST that takes the first node in a binary tree (its root) and returns true if it is the root of a BST, and false otherwise. (Hint: use recursion.) private class BinaryTreeNode public final T element: public BinaryTreeNode left. right public BinaryTreeNode(Key element) this element- element: left null: right-null: Your method must use the signature private static boolean isBST(Node rootD