The correct answer is - B. The passage states a credible source, the General State Archives of Greece.
The credibility of the passage can be seen in the fact that it comes from the institution in charge of historic archives in the country of Greece, which is the most reliable institution on that matter in the country. Since they recognize it as authentic, and that is from a reliable source, than it should be taken with a relative assurance that the passage is true and that it really describes the Ancient Greek societies.