challenge: What is the main focus of the podcast 'The Nightingale of Iran'?
  
  A. Exploring the history of Iranian migration to the United States
  B. Showcasing the musical talents of contemporary Iranian singers
  C. Uncovering the story behind Younes Dardashti's life and career
  D. Investigating the impact of political events on Iranian music in the 1960s
  Answer: 