Which of the following is true?

The correct statement indicates that both hydraulic systems 2 and 3 are operational. In the CRJ550, multiple hydraulic systems are implemented for redundancy and to ensure that essential flight control surfaces and systems can operate even if one hydraulic system fails. Each hydraulic system has dedicated functions and operates independently, allowing for a reliable overall system.

When both hydraulic systems 2 and 3 are indicated as operational, it suggests that critical systems relying on these hydraulics, such as landing gear operation and flight control surfaces, can function normally, contributing to the safety and performance of the aircraft. This ensures that any loss of a single system will not affect the overall operability of essential aircraft functions.

The other options imply that only one of the hydraulic systems is functioning or that neither is functional, which does not align with the correct assertion that both systems are operational. Operating with both systems would provide enhanced reliability and control in flight operations.