When a converging-diverging nozzle is operated at off-design conditions, a normal shock forms in the diverging portion. The nozzle can be assumed to be perfectly insulate from the surroundings. Then across the shock

• A. The velocity undergoes a jump but pressure and entropy remain unchanged
• B. The pressure undergoes a jump but velocity and entropy remain unchanged
• C. The velocity and pressure undergo a jump, but entropy remains unchanged because there is no heat transfer
• D. Velocity, pressure and entropy all undergo a jump