Explanation
The correct answer is (B) Sulphur dioxide.
Power stations, particularly those that burn fossil fuels like coal and oil, emit sulphur dioxide (SO2) into the atmosphere. When sulphur dioxide combines with moisture in the air, it forms sulphuric acid (H2SO4), a major contributor to acid rain. Acid rain refers to rain, snow, or any form of precipitation that has a pH value lower than the neutral value of 7, indicating increased acidity. Acid rain can have detrimental effects on ecosystems, forests, aquatic life, and infrastructure. Oxygen (option A), methane (option C), and carbon monoxide (option D) are not directly responsible for causing acid rain.