On what conditions may an exemption certificate，exempting from the requirement to install a fixed fire extinguishing system in a cargo space，be issued？（）

• A、The ship is constructed and solely intended for carriage of ore， coal， grain， unseasoned timber， non-combustible cargoes or cargoes which according to the Administration constitute a low fire risk
• B、Steel hatch covers and effective means of closing all ventilators and other openings to the cargo space are fitted
• C、A fixed deck foam system is be fitted in lieu of the cargo space extinguishing system
• D、The vessel is less than 10 000 gross tonnage