Answer:
D. It is two independent clauses joined by a coordinating conjunction.
Step-by-step explanation:
Clauses are groups of words containing at least a subject and a verb, they may be dependent or independent. Dependent clauses can not stand alone, therefore, they depend on another clause or sentence so they can make it sense. In opposition, Independent clauses can stand on its own and have full meaning.
In the sentence, "Roland, the artist, brilliantly captured the fading pastel light on his canvas" is an independent clause as it can be standing alone and has complete sense. "he preserved the sunset for future generations to enjoy" is another independent clause for the same reasons. And the word "and" acts as a conjunction to join both sentences.