What Are the Sources of Sulfur in the Atmosphere

Multiple Choice

What are the sources of sulfur in the atmosphere?

A) natural and human sources, in equal amounts
B) volcanoes and hot springs, but mostly (about 75%) human activities such as burning coal
C) mostly (over 90%) volcanoes and photosynthetic bacteria
D) mostly transportation modes, such as autos, trucks, and planes
E) decomposition and small amounts from pollution