What is a common source of bleed air for cabin pressurization?

The correct choice is based on the fundamental function and operation of aircraft systems. In many aircraft, cabin pressurization relies heavily on bleed air – compressed air drawn from the engines. Gas-turbine engine compressors are particularly crucial in this context, as they provide the high-pressure air needed for multiple systems, including cabin pressurization.

The air extracted from the engine compressors is not only used for keeping the cabin pressurized but also plays a role in other systems such as air conditioning and engine performance. This air can then be conditioned and directed into the cabin space to maintain a comfortable environment for passengers.

The other options do not serve as primary sources of bleed air for cabin pressurization. Environmental control systems typically utilize the bleed air but are not the direct source themselves. Air conditioning units also use bleed air but are part of the system that manages cabin temperature and airflow rather than generating the air pressure required for pressurization. Fuel tanks have no relevance to the provision of bleed air for pressurization purposes.