D. (A volcanic) eruption created an island in the sea near Japan.
Explanation:
D is the answer because it is the only answer choice that tells the reader how the island was created. The question asks for a sentence that tells you how the island was created. The other sentences only talk about the length of the island or the distance of the island from other islands in Japan. Therefore D is the answer because it tells you that the island was created by a volcanic eruption.
