If a linked list is empty and you insert a new node at the head, what are the head and tail pointers after the operation?

• A. Head points to the new node; tail remains null
• B. Head points to the new node; tail also points to the new node
• C. Head becomes null; tail points to the new node
• D. Tail points to the new node; head remains null

Answer: (B)

When a list has head and tail pointers, head always refers to the first node and tail to the last node. If the list is empty, both are null. Inserting a new node at the head puts that node as the only element, so it becomes both the first and the last node. Therefore, both head and tail will point to the new node, and the new node’s next (in a singly linked list) will be null since there are no other nodes.