How is the external flotation bladder of an immersion suit inflated?（）

A.It is inflated by a small CO₂ bottle that is automatically tripped when the front zipper is at the top of the zipper track

B.It is inflated by a small CO₂ bottle that is manually tripped

C.It is inflated by blowing through an inflation tube

D.It inflates by seawater bleeding into the inflation bladder and reacting with a chemical

经营者定价的主体是（）。

A.企业法人、其他经济组织和个人

B.企业和政府

C.市场

D.政府