Respuesta :
Eye witness account would be important to a historian, but I would think an unexploded shell would be more of an "artifact".
Answer:
D. an unexploded shell found on the battlefield
Explanation:
An artifact is a human-made object from a historical perspective. Weaponry that used shells would have been used during the time of the Civil War. The Civil War is considered to be a historical event. D is the most logical answer.