Using a gasoline engine requires burning gasoline.
And, of course, burning of gasoline produces toxic carbon monoxide.
Using a gasoline engine produces toxic carbon monoxide.
Toxic carbon monoxide is produced by what?
Options:
[a] gasoline engines
[b] Electric generators
[c] electric cars
[d] electricity
[e] solar panels
[f] cigarettes
[g] an engine
[h] ionization