They provide an alternative location to store information not related to any node, such as the number of nodes currently in the list. B III may not necessarily be true. Consider MergeSort which begins by placing each of the n items into a list of its own. C. Finding the predecessor and the successor of a list object. E. None of the above.
D are obvious.
In C , the successor can be found easily by following the next pointer. The predecessor can be found by traversing the entire list from the start and checking which object points to the given one. D A only deletes one node ahead. B only moves the current pointer ahead two nodes but leaves the list intact. C is bizarre, it creates a small loop in the list so that the next pointer of the next node will point back to the current node.