You are presented with the question "What may be stored in sedimentary rock for millions of years." and the following answer choices: 
- Sand castles
 - Chemical energy
 - heat energy
 - Millions of dollars.
 - A fuel source.
 - Energy.
 - In sediment
 - Stored animal fur.

Now knowing that carbon may be stored in sedimentary rock for millions of years and carbon is the fuel source, choose the best answer.


 

     A fuel source.    