The correct answer is D) it is a compound sentence.
The best option that describes sentence number 2 is “it is a compound sentence.”
A compound sentence joins two sentences using semicolon or the words “such”, “for” “but” or “and”. A compound sentence helps the writer to write colorful and more complete sentences that could interest the reader. So in the case of sentence number two of the question, it is a compound sentence that is separated by an “and” that complements the first idea of the sentence. “The right-handed twin always did the right thing, and the left-handed twin always did everything backward.”