Fact 1: Caffeine is a central nervous system stimulant.

Fact 2: Coffee is an excellent source of caffeine.

Given the two facts above, answer the question "What stimulates the central nervous system?" with the following options: 
- exercise
 - blood
 - rice
 - coffee
 - A drug.
 - a chime
 - ice
 - sweating


 

    coffee     