How can you determine the number of valence electrons in an atom of a representative element?

To find the number of valence electrons in an atom of a representative element, all you have to do is look at its group number. Ex: Group 1 (Hydrogen, Lithium, Sodium, Potassium, ect.) All have 1 valence electron

Most likely a is the answer - because  you generate   38 atp's but also consume an atp.   each atp gives approx. less than 4 kcal so probably a is the closest answer.