Answer:
b. Jupiter is the largest and most prominent planet in the solar system. It is the fifth planet in the solar system, followed by the planet Saturn, which is the sixth planet in the solar system.
Explanation:
"Largest and most prominent" is redundant.
To say that Saturn is the sixth planet after saying that Jupiter is the fifth planet is overly wordy.
“About Mars” is the Adjective Phrase.
Adjective phrase describes “what kind of which ones”
So for example here
“After school, I looked for books about Mars.”
“About Mars” describes the kind of books so that makes it an Adjective phrase.
I hope this helps.