Explanation:

Acid rain means the presence of excessive acids in rainwater.

• The causes of acid rain are Sulfur and Nitrogen particles which get mixed with the wet components of rain. Sulfur and Nitrogen particles which get mixed with water are found in two ways either man-made i.e as the emissions are given out from industries or by natural causes.
• Natural causes of acid rain are oxides of sulphur and nitrogen from volcanoes, swamps and plankton in the oceans.
• However, most of the acids are produced by human activities like power generation from fossil fuels which produces around 70% of the SO2 produced in the atmosphere. However, this is not a natural source but is an anthropogenic source. Hence all the options are correct.