The correct answer is A. Compressed Natural Gas.
CNG is a fuel made from natural gas that has been compressed to a much smaller volume. This makes it easier to store and transport. CNG is a clean-burning fuel that produces fewer emissions than gasoline or diesel fuel. It is also a renewable resource, as natural gas is formed from the remains of ancient plants and animals.
B. Cyanogen Natural Gas is not a real thing. Cyanogen is a poisonous gas that is not found in natural gas.
C. Condensed Nitrogen Gas is also not a real thing. Nitrogen is a gas that does not condense at normal temperatures and pressures.
D. Controlled Natural Gas is not a real thing. Natural gas is not a controlled substance.
CNG is used as a fuel for vehicles, buses, and other transportation. It is also used to generate electricity and heat homes and businesses. CNG is a safe and efficient fuel that can help reduce air pollution.