Which is true about lifeboats?

A、Davit launched lifeboats are always totally enclosed lifeboats.;

B、The call sign of the ship is marked on the bottom of the lifeboat.
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C、No matter what type of ship it is, lifeboats are made compulsory by SOLAS.;

D、Based on their launching methods, lifeboats may also be divided into open lifeboat, partially enclosed lifeboat, and totally enclosed lifeboat.