To determine which statement is true about the enzyme's performance based on the graph, you would typically look for the temperature at which the enzyme activity is at its peak.
If the graph shows a rise in enzyme activity up to a certain temperature (like 45 degrees Celsius) and then a decline afterwards, the correct statement would be:
c This enzyme works best at 45 degrees Celsius.
However, if the graph indicates maximum activity at 10 degrees Celsius or 60 degrees Celsius, then statements b or d would be correct, respectively.
Since I don’t have access to the actual graph, you will need to refer to it directly to identify which statement is accurate.