A is a run-on sentence, therefore it is incorrect.
B (leave as is) in incorrect because the original sentence combines independent and dependent clauses with a semicolon; semicolons are used to combine independent clauses.
C is incorrect for the same reason B is incorrect (the first clause in dependent).
D is the correct answer, as it properly uses commas to combine the clauses.
Hope this helps.
Answer:
D.
Explanation:
David won last year's spelling bee, <em>and </em>he also won first place in the talent show.
<em>And </em>is the coordinating conjunction in the sentence.
EDIT: <em>Apparently there is supposed to be a semi-colon for C.</em>
I would definitely run over the poetry in my head a few times
