单项选择题
A.check valve installed in the line
B.shut off valve at a manifold near the pump
C.quick disconnect union within ten feet of the pump
D.regulator in the line set at 125 psi
单项选择题 When fighting an oil or gasoline fire in the bilge，which of the following should NOT be used?（）
单项选择题 When fighting a fire with a portable dry chemical fire extinguisher，the stream should be directed（）.
单项选择题 When fighting a fire on a bulkhead using a portable carbon dioxide extinguisher，the stream should be directed at the（）.