The right answer for the question that is being asked and shown above is that: "a secondary pollutant" Acid rain occurs when sulfur dioxide in the atmosphere is oxidized in the presence of nitrogen dioxide. Acid rain is an example of a secondary pollutant.
A primary pollutant is any pollutant emitted directly from the source while secondary pollutants form when the hydrocarbons, and oxides of nitrogen and sulfur combine with sunlight combines with oxygen or water vapor present in atmosphere.
The acid rain is formed when the sulfur dioxide reacts with water to form acids which combines with rain and rain becomes acidic in nature.
