Inserting at the head of a singly linked list with a dummy node at the head simplifies which scenario?

• A. A dummy node simplifies insertion at head by avoiding empty-list special-case handling.
• B. It complicates memory management and requires extra cleanup.
• C. It requires freeing the dummy node after each insertion.
• D. It prevents insertions at the tail.

Answer: (A)

A dummy head (sentinel) at the front provides a fixed anchor so inserting at the head never has to treat an empty list as a special case. With the dummy in place, adding a new node to the front is just a simple pointer update: create the new node, set its next to the dummy’s current next, and then set the dummy’s next to the new node. You don’t need to check whether the list is empty or update a separate head pointer, because the dummy always sits at the front and the real first element is always dummy.next. The dummy remains in place as part of the list structure; you only move its next reference. This makes head insertions uniform and avoids the typical empty-list branching, while not complicating memory management or preventing tail insertions.