Which of the following describes the end condition of a linear traversal of a linked list?

• A. The traversal stops when the current node pointer is nullptr
• B. The traversal stops when the current node is the tail
• C. The traversal stops when the data equals zero
• D. The traversal stops after visiting two nodes

Answer: (A)

Understanding how a linear traversal works is about following each link from one node to the next until there are no more nodes to visit. In a singly linked list, each node points to the next one, and the last node points to null. That null pointer marks the end of the list, so the traversal stops when the current node pointer becomes null. This approach lets you safely process every node exactly once and know you’re done when you’ve hit the end.

Other ideas don’t hold up in general. Stopping when you reach the tail would require special handling to ensure you’ve processed the tail itself, which isn’t a universal end condition. Looking at the data value (for example, stopping when data equals zero) isn’t reliable because data can be anything and may include zeros inside the list. Stopping after visiting two nodes is arbitrary and ignores the actual length of the list.