To determine at what pH all of the amylase becomes denatured, you would typically need to adjust the pH settings in the simulation and observe the point at which the amylase loses its activity.
While I can't directly interact with the simulation or provide a precise answer from the simulation data, based on general biochemistry knowledge, amylase enzymes generally start to denature at pH levels that are significantly deviated from their optimal pH range, which is usually around 6.7 to 7.0 for human salivary amylase and slightly more acidic for pancreatic amylase.
From the options you've provided, the pH range where all amylase likely becomes denatured could be 5.5 and 7.5. This range indicates that both more acidic (5.5) and more basic (7.5) environments could result in denaturation of amylase.
You should test those pH values in the simulation to check if amylase is indeed denatured at either end.