Which of the following, if true, most seriously weakens the argument? A. In various parts of the world, civilizations that could not make iron from ore fashioned tools out of fragments of iron from meteorites. B. All the metallic Mayan artifacts that have been found by archaeologists are made of metals that are too soft for carving stone. C. The stone out of which these carvings were made is harder than the stone used by other Central American peoples. D. The technique that the Maya used to smelt gold and some other metals could not have been easily applied to the task of extracting iron from iron ore. E. Archaeologists disagree about how certain stone tools that have been found among Mayan ruins were used.