Consider an implementation of an unsorted circular doubly linked list. Suppose it has its representation with a head pointer only. Given the representation, which of the foliowing operations can be implemented in $O(1)$ time?

i$)$ Insertion at the front of the linked list

i$)$ insertion at the end of the linked list

ii$)$ Deletion of the front node of the linked list

iv$)$ Deletion of the end node of the linked list

I and II

$11$ and II

I, II and III

I, II$,$ III and IV