The correct answer is: A. at sea level.
The pressure cooker is a sealed pot that uses steam to cook food quickly. The steam is created by boiling water, which is then trapped inside the pot. The higher the pressure inside the pot, the higher the temperature at which water will boil. This means that food can be cooked at a higher temperature in a pressure cooker than it can be cooked in a regular pot.
At sea level, the atmospheric pressure is 1 atmosphere. This means that the pressure inside a pressure cooker that is operated with the pressure valve open will be 1 atmosphere. At the top of Mt. Everest, the atmospheric pressure is about 0.3 atmospheres. This means that the pressure inside a pressure cooker that is operated with the pressure valve open will be about 0.3 atmospheres. In an aeroplane flying at a height of 10,000 m, the atmospheric pressure is about 0.06 atmospheres. This means that the pressure inside a pressure cooker that is operated with the pressure valve open will be about 0.06 atmospheres.
Since the pressure inside a pressure cooker is higher at sea level than it is at the top of Mt. Everest or in an aeroplane flying at a height of 10,000 m, the highest inside temperature will be attained in the pressure cooker operated with the pressure valve open at sea level.
Here is a table that shows the atmospheric pressure at different altitudes:
Altitude | Atmospheric pressure
——- | ——–
Sea level | 1 atmosphere
10,000 ft | 0.3 atmospheres
20,000 ft | 0.1 atmospheres
30,000 ft | 0.06 atmospheres