Nitrogen monoxide and oxygen, both colorless gases, form a red-brown gas when mixed. nitrogen monoxide and oxygen are called the

Nitrogen monoxide and oxygen are called the reactants

Explanation:

Step 1: Given data

Nitrogen monoxide = NO

Oxygen = O2

Step 2: Balanced equation

2NO + O2 → 2NO2

This means that 2 moles of NO will be consumed and and 1 mole of O2 to produce 2 moles of NO2

This means NO2 is the prodcut that is produced.

NO +O2 react with eachother, to form NO2

This means nitrogen monoxide (NO) and Oxygen (O2) are called the reactants.

i think it's letter a.