Answer: A.The details show Fiorini has a history of criminal activity.
In this excerpt, we learn a little more about Fiorini. We are told that Fiorini was the Head of the International Anticommunist Brigade. We also learn that this brigade trained 23 Cuban exiles who set up guerrilla operations. These details allow us to develop a clearer picture of Fiorini and his past, which allows us to understand the character of this man better. By learning that Fiorini has a criminal past, his actions become more understandable, and this clarity contributes to developing the central idea of the text.