What is the primary purpose of a propellant tank pressurization system in a rocket?

What is the primary purpose of a propellant tank pressurization system in a rocket?

• A. To ensure a steady flow of propellant to the engine under varying external pressure and to prevent cavitation or boil-off.
• B. To cool the propellant before injection into the engine.
• C. To vent propellant during normal operation to relieve pressure.
• D. To measure propellant quality with sensors.

Answer: (A)