Which of the following statements is true about pumpkin pie preparation?

Starting pumpkin pie preparation at a higher heat is a common technique that helps to set the crust and create a desirable texture in the filling. By initially baking at a higher temperature, typically around 425°F (220°C), it allows the outer edges of the filling to firm up quickly while the inside can continue to cook through. This method helps to achieve a well-cooked pie with a nicely set filling and a crisp crust.

The other choices highlight methods or considerations that are not standard for pumpkin pie preparation. Baking in a preheated upper oven is not necessary for perfect results, as the heat distribution from a standard oven is frequently sufficient. Cooling the pie before serving is often recommended to allow flavors to develop and the filling to stabilize, making it easier to slice. Lastly, while pumpkin is the traditional choice for making pumpkin pie, other squashes could potentially be used, but their flavor and texture may differ significantly from the classic pumpkin pie experience that is expected.