The preorder traversal sequence of a binary search tree is 30, 20, 10, 15, 25, 23, 39, 35, 42. Which one of the following is the postorder traversal sequence of the same tree?(A) 10, 20, 15, 23, 25, 35, 42, 39, 30(B) 15, 10, 25, 23, 20, 42, 35, 39, 30(C) 15, 20, 10, 23, 25, 42, 35, 39, 30(D) 15, 10, 23, 25, 20, 35, 42, 39, 30

Consider the following operation along with Enqueue and Dequeue operations on queues, where k is a global parameter. MultiDequeue(Q){ m = k while (Q is not empty) and (m > 0) { Dequeue(Q) m = m – 1 } }What is the worst case time complexity of a sequence of n queue operations on an initially empty queue?(A) T(n) (B) T(n + k)(C) T(nk)(D) T(n 2 )