How is the external flotation bladder of an immersion suit inflated?（）
- AIt is inflated by a small CO2 bottle that is automatically tripped when the front zipper is at the top of the zipper track
- BIt is inflated by a small CO2 bottle that is manually tripped
- CIt is inflated by blowing through an inflation tube
- DIt inflates by seawater bleeding into the inflation bladder and reacting with a chemical