Which of the following statements are true?
◦ A PriorityQueue orders its elements according to the Comparator if a Comparator is specified in the constructor.
◦ A PriorityQueue orders its elements according to their natural ordering using the Comparable interface if no Comparator is specified.
◦ The priority of a PriorityQueue cannot be changed once a PriorityQueue is created.
◦ The priority of a PriorityQueue cannot be reversed once a PriorityQueue is created.