Answer:
Graph D
Explanation:
Enzyme activity will be highest at its optimum temperature.
At temperatures far below the optimum, the enzyme does not possess enough energy to work (i.e. the molecules aren't moving fast enough because of the higher temperature to increase collisions). This is called the activation energy.
At high temperatures, the enzyme can become denatured, warping its shape and catalytic activity. This means its activity will drop quite quickly until it can no longer function.
These features are all displayed in graph D.
