Which of the following areas must not be obstructed?

The correct answer highlights the critical importance of ensuring that hallways, stairways, and exits remain unobstructed. These areas serve as essential pathways for safe evacuation in the event of an emergency, particularly during a fire. Unobstructed access is crucial to allow quick movement for individuals leaving the building, as well as for rescue personnel entering to provide assistance. Blocking these areas can significantly impede evacuation efforts, potentially leading to injury or loss of life.

In contrast, while offices, storage rooms, and break rooms have their own safety considerations, they do not play the same fundamental role in emergency escape as hallways, stairways, and exits do. Therefore, maintaining clear and accessible routes in those designated areas is paramount for safety protocols in any building.