Respuesta :
The planets appeared to move backward in the sky occasionally.
The correct answer is option C
During 18th century the people used to think that the planets used to move backward in the sky and this is known as the Apparent retrograde motion.
The planets of the solar system appeared to be moving in backward direction.
At that time it was not explained properly that it seems to moving backward but actually it is not. Planets move around their respective orbits only.
