Which of the following is a known source of sulfur dioxide emissions?

Volcanic eruptions are a significant natural source of sulfur dioxide emissions. When a volcano erupts, it releases a variety of gases, including sulfur dioxide (SO2), into the atmosphere. This gas can have various environmental effects, including contributing to acid rain, which occurs when sulfur dioxide reacts with water vapor in the atmosphere. The sulfur dioxide released during eruptions can also lead to the formation of sulfuric acid droplets in the atmosphere, which can have cooling effects on the climate.

In contrast, while the combustion of natural gas does produce emissions, it primarily generates carbon dioxide and water vapor and contains much lower levels of sulfur dioxide due to the relatively low sulfur content of natural gas. Solar energy production and nuclear power generation are both energy sources that do not contribute to sulfur dioxide emissions, as they do not involve the burning of fossil fuels or sulfur-containing materials.