The correct answer is D. All 1, 2 and 3.
CNG is a cleaner fuel than gasoline or diesel because it produces fewer emissions. CNG produces almost no particulate matter, which is a major contributor to smog and air pollution. It also produces fewer oxides of nitrogen and sulfur, which are major contributors to acid rain. CNG also emits less greenhouse gases than gasoline or diesel, which helps to reduce climate change.
Option 1 is correct because CNG produces oxides of Sulphur and Nitrogen in very small amounts.
Option 2 is correct because CNG makes environment less polluted.
Option 3 is correct because CNG emits less greenhouse gases.