Answer:
The Serpent Mound has been attributed to the (A) Adena Indians.
Explanation:
The root of the Serpent Mound, who fabricated it and when, is still generally discussed. During the 1700s a clan of Delaware Indians told a man by the name of John Heckewelder that the Allegheny individuals fabricated the hill.
The Allegheny were a race of individuals who lived preceding the Adena culture, before roughly 1200 BC.
