There are two disadvantages to CO2 as a firefighting agent. One of these is the limited quantity available, and the other is ___________.

A
the lack of cooling effect on heated materials
B
that it cannot be used in a dead ship situation with no electrical power to the CO2 pump
C
that it breaks down under extreme heat to form poisonous gases
D
there is no effect on a class A fire even in an enclosed space
E