The five items: A, B, C, D, and E are pushed in a stack, one after other starting from A. The stack is popped four times and each element is inserted in a queue. Then two elements are deleted from the queue and pushed back on the stack. Now one item is popped from the stack. The popped item is
- A. A
- B. B
- C. C
- D. D
Answer: D. D
Explanation: Stack Push: A, B, C, D, E (Top).\nPop 4: E, D, C, B.\nQueue Enqueue: E, D, C, B (Rear).\nQueue Dequeue 2: E, D.\nStack Push: A (existing), E, D.\nPop 1: D.