On which principle is the working system of rocket based?

The working system of a rocket is based on the principle of conservation of momentum option [A]. This principle dictates that the total momentum of a system remains constant if no external forces act upon it. Rockets propel forward by expelling mass backward at high speeds, resulting in an equal and opposite reaction force propelling the rocket forward. This action-reaction pair demonstrates the conservation of momentum, where the momentum gained by the rocket is equal and opposite to the momentum lost by the expelled exhaust gases. This fundamental principle underlies the functionality of rocket engines and enables spacecraft to achieve propulsion in the vacuum of space where there is no air for traditional propulsion methods like jet engines. Therefore, the conservation of momentum serves as the foundational principle for the operation of rocket systems.