Final answer:
High-pressure steam commonly refers to steam with a pressure above 100 psi (D), which can range from 100 psi to several hundred psi depending on the application.
Step-by-step explanation:
The amount of pressure that is considered high-pressure steam varies based on context and application. However, the answer amongst the provided options would be D. Above 100 psi. High-pressure steam in industrial applications often exceeds 100 psi and can typically range from 100 psi to several hundred psi depending on the system's requirements. In power plants and for steam engines, the steam pressure can be significantly higher.
It's important to note that the pressure levels mentioned in the student's options are in psi (pounds per square inch), which is a unit of pressure commonly used in the United States. To give some context, 1 psi is roughly equal to 6.895 kPa (kilopascals).