The correct answer is B) 20 seconds. According to the U.S. Coast Guard regulations, when a CO2 fire suppression system is activated, there is typically a 20-second delay before the CO2 gas is actually released into the protected space. This delay is intended to provide personnel sufficient time to evacuate the area before the CO2 concentration becomes hazardous. The other options are incorrect because 10 seconds would not provide enough time to safely evacuate, while 60 and 90 seconds would be longer than the standard 20-second delay.