Please answer the following question: Fact 1: Carbon may be stored in sedimentary rock for millions of years. Fact 2: Carbon is the fuel source. Given the two facts above, answer the question "What may be stored in sedimentary rock for millions of years." with the following options: - Sand castles - Chemical energy - heat energy - Millions of dollars. - A fuel source. - Energy. - In sediment - Stored animal fur.
A:
A fuel source.