One way to implement a queue is to use a circular linked list. In a circular linked list, the last node's next pointer points at the first node. Circular lists do not have a head or a tail. Assume that we can maintain, at most, one iterator (e.g. a pointer) corresponding to a node in the list. For which of the following representations can the basic queue operations be performed in constant worst-case time? Justify your answers. Maintain an iterator that corresponds to the first item in the list. Maintain an iterator that corresponds to the last item in the list