Fact 1: The emission of sulfur dioxide causes acid rain.

Fact 2: Sulfur Dioxide and Asthmatics A highly reactive colorless gas smelling like rotten eggs, sulfur dioxide derives primarily from fossil fuel combustion.

Given the two facts above, answer the question "The emission of what causes acid rain?" with the following options: 
- Material carrying electricity
 - decomposing dead organisms
 - DNA damage and mutations
 - soil loss through hurricanes
 - Something that smells like rotten eggs
 - extreme heat and pressure
 - chemical compound NaCl
 - generating heat by burning


 

     Something that smells like rotten eggs    