Which of the following, if true, most strengthens the argument? A. Excavations in the central Asian region do not indicate whether invaders from southwest Asia settled permanently in central Asia. B. The V-shaped structures in central Asia were roughly 70 meters long, whereas the similar structures in southwest Asia were usually over 300 meters long. C. The walls of the structures in central Asia were made from earth, whereas the walls of the structures in southwest Asia were made of rock. D. The earliest examples of V-shaped walled structures in central Asia were of an advanced design. E. Some of the walled structures used for hunting in southwest Asia were built well after the earliest such structures were built in central Asia.