a1) Show the results of inserting 3 1 4 6 9 2 5 7 in this order, into an initially empty binary search tree (BST). a2) Then, show the result of deleting the root node of the final tree. b1) Show the result of inserting 2 1 4 5 9 3 6 7 in this order into an initially empty AVL tree. b2) When you perform a delete in an AVL tree, is it necessary to rebalance to make it an AVL tree again?