Answer:
c
Explanation:
The Newton's first law states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force. In outer space, and particularly in a location far from influences of gravity (and any other forces such as air resistamce) no external force is acting upon the rock, so it will continue its motion in a straight line with the same speed and the initial direction.
However if the astronaut continues to push it, he will apply a force to the rock, and the motion of tghe rock will be determined by the Newton's second law and the force the astronaut is extering to it