7. Which of the following statements about trees is most accurate? a. The purpose of AVL trees is to efficiently implement search algorithms. b. The order of search algorithms in all binary trees is the same c. The depth of a binary tree is as most O(log n) d. The balance factor of AVL trees is O or 1 8. True or false: a Red-Black tree with 128 nodes has at least one red node. a. True b. False 9. Is the following Red-Black tree (with leaf nodes hidden) valid? If not, whiclh property is violated? 30 20 10 45 63 15 37 50 60 35 40