Answer:
Answer is
a. Air at high temperature
Explanation:
The oxides of nitrogen are formed when the combustion / lightning / spark is carried out in the presence of air. High temperature is achieved during combustion which converts the nitrogen into NOx.
The answer is a because when very high temperature is achieved in air (mainly due to combustion process) the nitrogen reacts with oxygen to form nitrogen oxides.
b is not the answer because gasoline does not react with the nitrogen directly.
c is not the answer because air can be compressed to high pressures without any reaction between nitrogen and oxygen.
d is not the answer because air we breath in is at atmospheric pressure and both gases in air doe not react with each other.
