Answer:
A. less expensive because most reserves are in the United States
Explanation:
Natural gas is less expensive because in the united states there are huge amount of reservoirs present. According to the research, the United States has about 475 trillion cubic feet of proved reserves and 2,392 trillion cubic feet of unproved reserves of dry natural gas. It is a clean source of energy comparatively coal and fossil fuel because it produces less amount of carbondioxide and other pollutants in the atmosphere so that's why the natural gas is less expensive and prefers in usage.