Consider the following statements

a) An astronaut accidentally gets separated from his small spaceship accelerating in interstellar space at a constant rate of 100 m s^–2. The net force acting on the astronaut, once he is out of the spaceship, is zero. (Assume that there are no nearby stars to exert gravitational force on him.)

b) The same force for the same time causes the same change in momentum for different bodies.

c) Force is not necessary for changing the direction of momentum, even if its magnitude is constant.

Which of the above statements is/are correct