The correct answer is the last option "an explanation of the natural world" because myths try to explain natural occurrences and express beliefs of a certain culture, in this case, we are talking about Greek mythology in which it is clear that the elements in myths were early man's desire to explain the universe, often in anthropomorphic figures, as Zeus has the power of thunder or in this excerpt helios where the one who brings the light into the day. One of the most important elements of Greek myths is magic realted to powers in nature. It's not "A description about a historical event" because myth is the explanation of the origins of the life and natural world in ancient times where people couldn't rely on science so they create stories to provide an explanation about their world but they are not necessarily true or historical as we know today that thunder comes from clouds instead of believing that it was Zeus the god of thunder. On the other hand, It's not "a lesson about difficulties of life" because this myth of Helios talks about his duties as a god and also a description of the chariot and himself, it doesn't talk about his problems or how he solve them to teach us a lesson. Finally, it's not "an explanation of human behavior" because it's very difficult to identify our behavior as humans in comparison to gods in Greek myths. They are different from us, they have power and abilities in order to create and sustain the world. It is possible to find an explanation of human behavior in other stories where humans were part of the plot but not in this specific case.