Answer:
The correct answer is option c. "there are no reaction forces on them".
Explanation:
When an astronaut is traveling around the Earth's orbit she or he experiences a sensation of weightlessness. This happens because there are no reaction forces on them, they only experience the gravitational force which is not a contact force. This sensation of weightlessness is similar of the sensation that someone experience in an amusement park when is it traveling in a free-falling ride.
