单选题Large volumes of carbon dioxide are safe and effective for fighting fires in enclosed space, such as in the pumproom, provided that the（）.Apersons in the space wear gas masksBpersons in the space wear damp cloths over their mouths and nostrilsCventilation system is secured and all persons leave the spaceDventilation system is kept operating
单选题
Large volumes of carbon dioxide are safe and effective for fighting fires in enclosed space, such as in the pumproom, provided that the（）.
A
persons in the space wear gas masks
B
persons in the space wear damp cloths over their mouths and nostrils
C
ventilation system is secured and all persons leave the space
D
ventilation system is kept operating
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