Fossilized bones from the hominids Australopithecus robustus and Homo erectus were chemically analyzed. The robustus bones contained a lower ratio of strontium to calcium than did the erectus bones. The lower the ratio of strontium to calcium in fossilized hominid bones, the more meat the hominid had in its diet. H. erectus is known to have eaten meat. The statements above, if true, most strongly support which one of the following? ['The diet of H. erectus was richer in calcium than was the diet of A. robustus.', 'The diet of A. robustus included at least some meat.', 'The diets of A. robustus and H. erectus both contained less strontium than calcium.', 'The meat in the diet of H. erectus was higher in strontium than was the meat in the diets of other hominids.']