Answer: Country B has a comparative advantage over the United states in coal. It takes country B two fewer hours than the U.s. to produce 1 ton of coal.
Explanation: when a natural resource is more available and easily accessible, this gives a country an advantage over other countries because it takes less time to attain that resource and prepare to sell and trade it. When a country doesn't have to put as much time and money into producing something they have the greater advantage.