Respuesta :
Answer:
The answer to your question is the third option
Explanation:
 Chemical reaction
            4NH₃  +  5O₂  ⇒   NO +  H₂O
Count the number of elements in the reactants and products
           Reactants     Elements   Products
             4             N          1
             12             H          2
             10             O          2
All the elements are unbalanced
Let's add the following coefficients
           4NH₃  +  5O₂  ⇒   4NO +  6H₂O
           Reactants     Elements   Products
             4             N          4
             12             H          12
             10             O          10
Now the reaction is balanced
Answer:
Add a coefficient 4 before NO and a 6 before H2O.
Explanation: