气相色谱分析中常用的载气有（）.

A.氮气

B.氧气

C.氢气

D.甲烷

During transfer operations，a quantity of propylamine spills on deck. According to the Chemical Data Guide，the correct procedure would be to（）.

A.immediately flush the spill with large quantities of fresh water

B.cover the contaminated surface with soda-ash-soaked lime solution

C.add sodium bisulfate on the contaminated surface and spray it down with water

D.move to a position upwind of the spill and allow the product to boil off