Final answer:
The device used for training astronauts and jet fighters is a centrifuge. It simulates the accelerations experienced during rocket launches and atmospheric reentries, exposing trainees to high G-forces.
Step-by-step explanation:
The device used for training astronauts and jet fighters is a centrifuge. A centrifuge is a machine that rotates at high speeds, creating a centrifugal force that simulates the accelerations experienced during rocket launches and atmospheric reentries. It exposes trainees to high G-forces, helping them build tolerance and prepare for the physical demands of space travel and high-speed flight.
During the training, the rider sits in a cage that pivots outward during rotation, allowing the total force exerted on the rider by the cage to be along its axis at all times.
Other devices mentioned in the question, such as the simulated cockpit, G-force simulator, and zero-gravity chamber, may also be used for training purposes, but the primary device specifically mentioned for training astronauts and jet fighters is the centrifuge.
Therefore answer is a. Centrifuge.