Which Is True of Environmental Tobacco Smoke (ETS)

Which is true of environmental tobacco smoke (ETS) ?

A) Sidestream smoke and mainstream smoke, which are equally dangerous, are produced.
B) Sidestream smoke and mainstream smoke, which are equally safe, are produced.
C) Mainstream smoke and sidestream smoke, the latter of which is more dangerous, are produced.
D) Sidestream smoke and mainstream smoke, the latter of which is ore dangerous, are produced.