challenge: What are the two house tours currently offered to visitors at the Pearl S. Buck House National Historic Landmark?
  
  A. Pearl S. Buck: Human Rights Advocacy and Pearl S. Buck: Life and Legacy Tour
  B. Pearl S. Buck: Taking Action and Pearl S. Buck: Life and Legacy Tour
  C. Pearl S. Buck: Activism and Pearl S. Buck: Cultural Heritage Tour
  D. Pearl S. Buck: Taking Action and Pearl S. Buck: Art and Literature Tour
  Answer: 