Which of the following is a characteristic of passive fire protection systems?

Passive fire protection systems are designed to prevent the spread of fire and smoke within a structure without the need for active intervention or mechanical systems. Option D accurately describes this characteristic, as these systems often use physical barriers such as walls, floors, and doors made from fire-resistant materials to contain the fire and protect different areas of a building.

By using physical barriers, passive fire protection systems help to compartmentalize a building, limiting the size and spread of a fire, thereby allowing for safer evacuation of occupants and reducing damage to property. This containment strategy works independently of utility services and does not require any human action once installed, which emphasizes its role in enhancing overall fire safety.

In contrast, the other options highlight characteristics that are typical of active fire protection systems, which involve equipment or systems that require a human response or operate based on detection of heat, smoke, or fire. Such systems include sprinklers and alarms which are designed to act when certain conditions are met, thus distinguishing them clearly from passive systems.