You are presented with the question "what can carbon be stored in for millions of years?" and the following answer choices: 
- limestone
 - fossil fuels
 - hydrocarbons
 - graptolites
 - fish
 - humans
 - h2o
 - layers of fat

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


 

 limestone        