Expand the BST implementation we had in class, by implementing the following extra functions: 1) (20 points) write a function I next (INode P) that returns the successor of the node that is pointed by P based on in order traversal 2) (20 points) Write a function woid print Level (int Level) that prints all the nodes at the input level. If the level does not exist, output a proper error message. 3) (30 points) write a function bool isBSTO, which returns true if the current binary tree is a BST, and false otherwise. Note that: checking whether every node contains a value larger than its left child and smaller than its right child .... Does not work for all cases 4) (30 points) write a function TLCS(T& a, T&b) that returns the smallest common ancestor of two nodes in a BST. If the tree is empty, or if it has less than three nodes, it retums -1. For example the LCS(6.12) = 10 10 25 12 20 30 Please submit your answer on eLearning only, submit your code as a text file .cpp, and please do not submit the entire BST class, just the functions you implemented in this assignment