Retrograde motion describe the

A backward motion of the stars relative to Earth
B uniform circular motion exhibited by the planets
C irregular speeds at which the planet travel.
D backward motion of the planets with respect to the stars

I think the answer is A
But my book state that it in a backward motion but I don't understand

I already answered this question for you and the answer was not A.

Check my previous answer.

You have two "backward motions" to choose among.

http://www.jiskha.com/display.cgi?id=1269739195

You are correct that retrograde motion refers to a backward motion, but your book states it in a slightly different way. Let me explain it to you in more detail.

Retrograde motion is an apparent backward motion of a celestial object, such as a planet, when observed from another celestial object, such as Earth. It can be observed when a planet appears to move in the opposite direction than its usual path across the night sky. This motion is different from the regular, forward motion that planets exhibit most of the time.

The reason behind retrograde motion is the complex combination of the Earth's orbit and the orbit of the observed planet around the Sun. As Earth orbits the Sun, it sometimes catches up to or overtakes a planet in its own orbit. From our perspective on Earth, it appears as if the planet starts moving backward in the sky for a period of time before resuming its normal, forward motion. This gives rise to the term "retrograde" because it seems like the planet is going against its usual direction of motion.

So, the correct answer to your question is D: Retrograde motion refers to the backward motion of the planets with respect to the stars.