The correct answer is B. Sulphur dioxide.
Sulphur dioxide is a gas that is emitted by power stations when they burn fossil fuels such as coal and oil. It is also emitted by other industrial processes, such as metal smelting and paper production. Sulphur dioxide can react with water in the atmosphere to form sulphuric acid, which is a major component of acid rain.
Carbon dioxide is another gas that is emitted by power stations. However, carbon dioxide does not cause acid rain. Instead, it is a greenhouse gas that contributes to climate change.
Helium and nitrogen are both inert gases that do not react with other chemicals. They are therefore not a major cause of acid rain.
Acid rain is a major environmental problem that can have a significant impact on human health and the environment. It can damage forests, lakes, and rivers, and it can also corrode buildings and other infrastructure.