Fragments of charred antelope bone have recently been found at a million-year-old settlement of Homo erectus, an early human species. This discovery demonstrates that humans were making controlled use of fire to cook meat at a very early stage of their development. The argument above makes which of the following assumptions? ['The diet of Homo erectus consisted in large part of antelope meat.', 'Homo erectus could not have eaten antelope meat unless the meat had been cooked.', 'The antelope bones were charred in a fire controlled by humans.', 'Early human settlements can be identified by the presence of charred antelope bones.']