Many anthropologists believe the Native Americans of Poverty Point were not isolated, despite the group's hunter-gatherer lifestyle. In fact, evidence of a more social lifestyle, marked by major involvement in trading has been discovered. Which piece of evidence has been found to BEST support this claim?

A Buried deep within Mound A, archaeologists have uncovered evidence of a trading center. They have discovered signs, maps, drawings, and structures used at trading centers.

B Poverty Point was surrounded by tall walls on all sides, and it could only be accessed through a gate. This was a common characteristic of trading posts to prevent stealing.

C Archaeologists have found materials like copper and mica at Poverty Point that have not been found elsewhere in Louisiana. These items would have likely been brought by traders.

D Maps from early exploration of America have been found throughout Louisiana. Many of them show Poverty Point as a major trading location, marked by the recognizable "Mound A."