Option (C) 'samples of rock materials from the moon' is the correct answer because geography, as defined in the context, is concerned with understanding the earth as the home of human beings and studying elements that have sustained them. The other options—traveller's accounts, old maps, and ancient epics—all provide information about places, regions, and human-environment interactions on Earth. Moon rock samples, while scientifically valuable, do not serve as a source of geographical information about the Earth.