What happens when you insert a node at the head of a linked list?

• A. The new node becomes the tail
• B. The new node points to the current head, and the head is updated to the new node
• C. The list remains unchanged
• D. The new node is inserted after the tail

Answer: (B)

Inserting at the head means making the new node the first element in the list. To do this, you set the new node’s next pointer to point to the current head, and then update the head reference to the new node. This sequence places the new node in front of the existing nodes, so the rest of the list keeps its order after the new head. If the list was empty, the new node points to null and becomes the sole element (and, if you track a tail, it would also point to this new node). The tail would not change in a non-empty list, and inserting after the tail or leaving the list unchanged would not place the new node at the front.