So this is a typical bimolecular second order chemical reaction that takes place inside our body under enzyme catalyzed conditions. Now, according to this equation, we see that the enzyme catalyze reactions, when they take place inside our cells, the rate of the enzyme, the rate at which the enzyme actually catalyzes that reaction depends on three different things. Number one, it depends on the concentration of that substrate. Number two, it depends on the concentration of that enzyme. And number three, it depends on the rate constant, KCAD divided by Km. Now, A makes sense because if we have more substrate, more substrate is going to bind on the active side and more that substrate will basically be transformed into the product as a result.