Metal rings recently excavated from seventh-century settlements in the western part of Mexico were made using the same metallurgical techniques as those used by Ecuadorian artisans before and during that period. These techniques are sufficiently complex to make their independent development in both areas unlikely. Since the people of these two areas were in cultural contact, archaeologists hypothesize that the metallurgical techniques used to make the rings found in Mexico were learned by Mexican artisans from Ecuadorian counterparts. Which of the following would it be most useful to establish in order to evaluate the archaeologists' hypothesis?
(A) Whether metal objects were traded from Ecuador to western Mexico during the seventh century
(B) Whether travel between western Mexico and Ecuador in the seventh century would have been primarily by land or by sea
(C) Whether artisans from western Mexico could have learned complex metallurgical techniques from their Ecuadorian counterparts without actually leaving western Mexico.
(D) Whether metal tools were used in the seventh-century settlements in western Mexico
(E) Whether any of the techniques used in the manufacture of the metal rings found in western Mexico are still practiced among artisans in Ecuador today