Which choice most logically completes the text?

|Question 15Verbal

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At Alligator Reef (Florida Keys), coral colonies experiencing degradation—a problem facing reefs globally—have been enhanced with transplanted fragments of elkhorn (a stony coral). This is a useful restoration approach but is challenging at scale since it involves cultivating and individually moving young stony coral pieces. In 2025, Samapti Kundu and her team announced a new approach: coating reef substrates with a simple-to-apply substance, made with inexpensive and abundant core ______

offers a means of reef restoration that likely allows much broader implementation than the approach used at Alligator Reef does.

is likely to require more costly components to ensure its stability when used for coral colonies as degraded as those at Alligator Reef.

should be most beneficial for restoring reefs that predominantly consist of elkhorn coral colonies.

should be able to simulate healthy reef signals even more closely when it is