Given the index at which a new element is to be inserted in an array with N elements, the insertion operation will require O(N) time.

Given the reference to the head of a linked list with N elements, all other nodes can be accessed in almost equal time.

Given the reference to the first index in an array with N elements, the time required to access the remaining indices vary significantly - by O(N) time in the worst case.

Given the reference of the node after which a new node is to be inserted into a linked list with N elements, the insertion operation will require O(N) time.