What is the source of oxides of nitrogen?

Q. What is the source of oxides of nitrogen?

A.            Powerstations and industries using fossil fuels only

B.            exhaust fumes of motor vehicles only

C.            incomplete burning of wood

D.            Powerstations & industries using fossil fuels and exhaust fumes of motor vehicles

Answer: Powerstations & industries using fossil fuels and exhaust fumes of motor vehicles