Which of the following is an example of an active fire protection method?

An automatic fire sprinkler system is considered an active fire protection method because it actively engages in combating fire once a fire is detected. Upon sensing heat or smoke, these systems automatically activate to suppress or extinguish the fire using water or other extinguishing agents. This response serves to control the fire's spread and minimize damage, actively protecting both lives and property during a fire emergency.

In contrast, other methods listed, such as fire-resistant building materials, serve as passive fire protection. They are designed to slow or prevent the spread of flames and smoke but do not require activation to function; they remain effective as long as the materials themselves are intact. Compartmentation strategies similarly focus on the design and layout of a building to contain fires, utilizing physical barriers, yet they also do not involve active intervention during a fire event. Ventilation control, while important for firefighting operations and smoke management, involves managing airflow rather than actively extinguishing or suppressing fire.