The following Java method implements in a simply-linked list. It modifies the list by moving the last element to the front of the list. Some part of the code is left blank. Choose the correct alternative to replace the blank line. Void move_to_fronto { Node p. 9; if ((firstNode != NULL && firstNode.next != NULL)) {q = NULL; p = firstNode; while (p.next !=NULL) {q=p;p=p.next; } Select one: O a. q = NULL; p.next = firstNode; firstNode = p; O b. q.next = NULL; firstNode = p; p.next = firstNode