The correct option is C Maybe the temperature in the lab is not right.
If we look at the important characteristics for enzyme action, we will see that
1. These reactions are highly efficient.
2. These are highly specific.
3. These are highly temperature dependent. These reactions operate most efficiently at a temperature called the optimum temperature.
From the second and third point, we can conclude that enzymes react only with very specific substances. That's why Enzo didn't find it react with most substances.
It's also possible that the temperature in his lab is not quite right for the enzyme action.