单选题Foam is a very effective smothering agent and（）.Ait provides cooling as a secondary effectBworks well on extinguishing electrical firesCcan be used to combat combustible metal firesDAll of the above
单选题
Foam is a very effective smothering agent and（）.
A
it provides cooling as a secondary effect
B
works well on extinguishing electrical fires
C
can be used to combat combustible metal fires
D
All of the above
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