challenge: According to the provided context, which of the following statements is true about countries interested in joining ASEAN?
  
  A. No countries outside Southeast Asia have been allowed to join ASEAN
  B. Countries outside Southeast Asia have not expressed interest in joining ASEAN
  C. Only countries within Southeast Asia have expressed interest in joining ASEAN
  D. Several countries outside Southeast Asia have expressed interest in joining ASEAN
  Answer: 