The correct answer is Hydrogen (Option 3). Here`s why:
Option 1 - Diesel is responsible for emitting particulates, greenhouse gases, and other contaminants like sulfur and nitrogen compounds which contribute to air pollution.
Option 2 - Coal, when burned, releases substances like sulfur dioxide, nitrogen oxides, and mercury compounds, which are harmful to both the environment and the health of living beings.
Option 3 - Hydrogen is the cleanest fuel among these options because it produces only water vapor when it is burned. Thus, it doesn`t contribute to air pollution, making it environmentally friendly.
Option 4 - Kerosene, when burned, emits a significant amount of pollutants, including carbon-containing particles, which contribute to climate change and respiratory diseases.
So, the correct choice is indeed Hydrogen (Option 3).