单选题Diesel engines are considered safer than gasoline engines because（）.Athey are more heavily builtBthe fuel used is less volatileCthey can be easily reversedDthey operate at a lower speed
单选题
Diesel engines are considered safer than gasoline engines because（）.
A
they are more heavily built
B
the fuel used is less volatile
C
they can be easily reversed
D
they operate at a lower speed
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