6225
Delimitation of international boundaries in the vicinity of Lake Chad , the lack of which led to border incidents in the past , has been completed and awaits ratification by Cameroon , Chad , Niger , and Nigeria .
 Lake Chad, Cameroon, Chad, Niger, Nigeria
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Lake Chad, Cameroon, Chad, Niger, Nigeria