Which statement is true about a circular singly linked list?

• A. The list has a NULL termination.
• B. The last node’s next pointer is NULL.
• C. The list cannot be traversed backwards.
• D. The last node points back to the head, forming a loop.

Answer: (D)

In a circular singly linked list, the defining trait is that the last node links back to the first node, creating a loop. This means there is no NULL termination like in a linear singly linked list; instead, following next pointers eventually brings you back to the head. That loop-back behavior is what makes the structure circular and distinguishes it from a normal list. So the statement that the last node points back to the head, forming a loop, captures this essential property.

The other descriptions don’t fit because a circular list doesn’t end with NULL, so there isn’t a NULL termination and the last node’s next isn’t NULL. Also, while you can’t traverse backwards in a singly linked list, that’s true for all singly linked lists and isn’t what uniquely defines the circular form.