4.1 The Queue 1. True or False? Explain your answers. a. A queue is a "first in, first out" structure. b. The element that has been in a queue the longest is at the "rear of the c. If you enqueue five elements into an empty queue and then dequeue five of the queue. elements, the queue will be empty again. d. If you enqueue five elements into an empty queue and then perform the isEmpty operation five times, the queue will be empty again