The typical pressurisation ranges when operating in AUTO mode are:

• A. Isobaric and differential ranges
• B. Isobaric and absolute ranges
• C. Differential and gauge ranges
• D. Isothermal and differential ranges

Answer: (A)

In auto mode, the pressurization system is controlled using two common references: keeping the cabin pressure constant at a chosen cabin altitude (isobaric control) and keeping a constant difference between cabin pressure and outside ambient pressure (differential pressure control). These are the two typical ranges the system can target as you climb or descend, depending on flight conditions and safety margins. The other terms don’t describe standard auto-control targets for cabin pressurization: absolute pressure relates to pressure relative to a vacuum and isn’t used as the control reference in this context; gauge pressure is just a measurement type, not the control range; isothermal refers to temperature behavior, not pressure control.