Answer: Oil
Step-by-step explanation:
The united states is the leading producer of the crude oil and gas and holds more coal reserves as compared to the other countries.
The crude oil production is accounted to be largest in the United States which accounts for more than 10.9 million barrels per day.
This is a huge number which is not been expected from any of the other countries. The United states is the leading country when it comes to fossil fuels.