<h2>The answer is option b "free energy is zero"</h2>
Explanation
The reaction that has negative free energy are called exergonic reactions that means the reactants have more free energy than the product formed.
The reaction that has positive free energy are called endergonic reactions that means the final state or the products formed have more free energy than the initial state or the reactants.
The reaction that has zero free energy occurs when the free energy of both reactants and the products are same hence the rate of formation of products and reactants are equal.
Therefore, when reactants and products are being formed at an equal rate the free energy is zero.
