複選題41. Consider an AVL tree that results from successively inserting keys 2, 4, 5, 3, 8, 7, 1, 6, 9 into an initially empty tree. Which of the following statements are true? (A) The tree height is 4. (B) Key 3 and key 5 have the same depth. (C) Key 2 and key 8 have the same height. (D) Key 6 is a leaf. (E) Key 7 is the parent ofkey 9.