The correct answer is c. challenging the credibility of sources. Ramona asks in a questionable way if the information or evidence from Pettit's book comes from a fictional source. Han has backed up his information with the evidence of a review of Giovanni Fiorini's book. Pettit makes sure that the material in this book has been written by a narrator and not by a historian.
Han applies option c- he is challenging the credibility of sources. Ramona ,surprised, asks him if the evidence from Pettit's book was from fictional sources. Hans supports his claim through a review of Giovanni Fiorini's book. The material from this book which had been written by a story-teller and not by a historian was used by Pettit.
Option a- is wrong. Hans is not determining new research goals. He is questioning the credibility of sources.
Option b-is wrong. Hans is evaluating what an author said about Giovanni Fiorini's book. The material from this 'great' source was used by Pettit in <em>his </em>book.
Option d is wrong. Ramona is asking clarifying questions. She wants Hans to justify his claim. This states that the credibility of sources can be questioned.