Question

which impurity found in coal can lead to acid rain in the atmosphere? sulfur oxygen hydrogen lead

Explanation:

When coal containing sulfur is burned, sulfur reacts with oxygen to form sulfur dioxide ($\ce{SO_2}$). Sulfur dioxide can further react in the atmosphere to form sulfuric acid, which contributes to acid rain. Oxygen is a reactant in combustion, hydrogen in coal combustion forms water, and lead is a pollutant but not a primary cause of acid rain from coal.

Answer:

A. sulfur