Hello, Brainly User!
A heterogeneous equilibrium reaction is when there are different phases in the reaction. An equilibrium reaction is a reaction that can go in both the forward and reverse directions, and the concentrations of the reactants and products remain the same.
So therefore, your answer is A. Heterogeneous!
Hope i helped and i was honored to answer your question!
Have a great day..
-Philaeagles14