Which hydraulic systems must be available to lower the nose landing gear?

The correct answer pertains to the operation of the nose landing gear on the Canadair Regional Jet. The nose landing gear relies specifically on the hydraulic systems designated for such operations. In the PSA Airlines Canadair Regional Jet, hydraulic system 3 is primarily responsible for landing gear operations, while system 2 serves as a backup in case system 3 fails.

Since the nose landing gear must be safely lowered and locked into position before landing, the reliance on hydraulic systems 2 and 3 ensures redundancy and increases the reliability of the landing gear deployment process. If system 3 experiences a malfunction, system 2's availability allows for a successful deployment, thereby ensuring that the aircraft can land safely.

The other combinations do not align with the aircraft's hydraulic system design and operational procedures, reducing their effectiveness for this specific task.