The graph shows the effect of pH on the rate of reaction to three different enzymes. What does the graph show?

Answer:
Regarding the effect of pH on the reaction rate of three different enzymes, what the graph shows is that each enzyme works better at different pH (option A).
Explanation:
Enzymes are specialized protein molecules whose function is to contribute to faster reactions with lower activation energy. To fulfill this function, enzymes must be in an optimal range of temperature and pH.
The graph shows three enzymes, one in an acidic medium, one in a neutral medium and one in a basic medium. The reaction rate of each enzyme is similar, indicating that each is working at an optimum pH. The best interpretation that can be drawn from the graph is that each enzyme works best at a different pH.
The other options are not correct because:
B. The variable "temperature" is not included in the graph.
C and D. Since the comparison of the reaction rate of a single enzyme at different pH is not being made, the graph is not useful to indicate whether an enzyme works better in acidic or basic conditions.