Final answer:
When approaching a stop sign that is not marked by a crosswalk, drivers should stop their vehicles before entering the intersection.
Step-by-step explanation:
When approaching a stop sign that is not marked by a crosswalk, drivers should stop their vehicles before entering the intersection. This is because stop signs are placed at intersections to regulate traffic and ensure safety. By stopping before entering the intersection, drivers can thoroughly assess the traffic situation from all directions before proceeding.