22. Here is an array which has just been partitioned by the first step of quicksort 3,0,2,4,5,8,7,6,9 Which of these elements could be the pivot? d. 6 c. (b) or (c) 23. Ose difference between a queue and a stack is a. Queues require dynamic memory, but stacks do not. b. Stacks require dynamic memory, burt queues do not c Queues use two ends of the stracture; stacks use only one d. Stacks use two ends of the stracture, qucues use only on The operation of processing each element in the list is known as a Sorting b. Merging c. Inserting d Iterating 25. Consider the array implementation of a stack lic class ArraystackeAnytype> AnyType L1 data int topotstack What must be the initial value of toporstack? d. null 6. Which statement is correct? a. An AVL tree is a balanced binary search tree b. An AVL tree is a noermal binary search tree e An AVL tree is a 2-3 tree. d. An AVL tree is usually not a binary search tree. 27. Adding an element to a stack ADT means: a. Placing the element at the rear end b. Placing the element at the top. c. Placing the element at the front end d. None of the above. 28. Heap sort is found to be very efficient a. in time complexity b. regarding the storage and runtime overhead involved. c. with regard to the storage requirement d. None of the above