Reducing which of the following can help mitigate acid rain?

The correct choice focuses on sulfur dioxide emissions because they are a primary contributor to the formation of acid rain. When sulfur dioxide is released into the atmosphere, it can react with water vapor and other chemicals to form sulfuric acid. This acid eventually falls to the ground as precipitation, leading to the phenomenon known as acid rain. By reducing these emissions, the amount of sulfuric acid produced decreases, which directly helps in mitigating the effects of acid rain.

In contrast, while carbon monoxide, ozone, and volatile organic compounds are significant pollutants that can affect air quality and contribute to other environmental issues, they do not play a direct role in the chemical reactions that form acid rain. Therefore, managing sulfur dioxide emissions is critical for addressing the specific problem of acid rain and its harmful impacts on ecosystems, water sources, and structures.