The correct answer is B. The passage states a credible source, the General State Archives of Greece.
Explanation
What makes the passage seem credible? When a writer wants his text to be credible, he must go to sources that give credibility to what he has written, these sources can be classified into primary, secondary, and tertiary according to their level of fidelity concerning the subject, for example, a primary source can be diaries, speeches, interviews, letters, investigations, paintings; secondary sources are textbooks, encyclopedias, biographies, reviews, etc; finally, the tertiary sources can be bibliographies or information catalogs. Therefore, it can be considered that the files from which the information on slavery in ancient Greece was obtained are reliable because they are obtained from the General State Archive of Greece, so the correct answer is B.