Which statement about purge cycles is accurate?

Which statement about purge cycles is accurate?

• A. A brief purge of outdoor or stale air from the ductwork to refresh air; used during start-up, after occupancy changes, or in ventilation-only periods
• B. Purges all air from the building during every cycle
• C. Purges only during nighttime operation
• D. Purges indoor air into the outdoors at all times

Answer: (A)