V-shaped walled structures in central Asia were used by prehistoric hunters who drove hoofed animals into an enclosure at the point of the V. The central Asians who built these structures probably learned this hunting technique from invaders from southwest Asia, because the arrival of invaders from a region in southwest Asia where similar structures had long been used coincides roughly with the building of the earliest of such structures in central Asia.
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．(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.
