The correct answer is C) Mound builders had a very extensive trade network.
The burial artifacts found in the Harlan Mound site proved that Mound builders had a very extensive trade network.
We are talking about the Spyro mounds located in Eastern Oklahoma. This place is an archeological site that belonged to the northern Caddoan Mississippian from the 900 CE to 1450 CE. The site is located in the town of Spiro, in the banks of the Arkansas River. The Harlan artifacts are dated around 1050 to 1250 CE.
The other options of the question were A. Mound builders lived in Oklahoma 9,000 years ago. B. Mound builders invented Clovis spear points. D. Mound builders hunted megafauna.
