How many hydraulic pumps does the CRJ utilize?

The CRJ utilizes a combination of hydraulic pumps that ensure optimal function of its hydraulic systems, which are critical for controlling various aspects such as flight control surfaces, landing gear, and brakes. The aircraft is equipped with four electric hydraulic pumps, which provide redundancy and can operate independently, enhancing the reliability of the hydraulic system. Additionally, there are two engine-driven hydraulic pumps that operate automatically when their respective engines are running, supplying hydraulic fluid under pressure necessary for various systems.

The combination of electric and engine-driven pumps allows for flexibility and redundancy. Having both types ensures that the aircraft can rely on electrical power for hydraulic pressure during operations such as ground handling or emergency situations, while the engine-powered pumps are there for normal operation during flight. This setup is designed to maintain hydraulic power in case of a pump failure, thus ensuring the safety and functionality of the aircraft systems.

The other options suggest incorrect configurations of pumps that do not align with the actual design and operational philosophy of the CRJ aircraft. The choice of four electric pumps and two engine-driven pumps is representative of the system's design to enhance efficiency, reduce weight, and ensure operational reliability in various flight conditions.