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The most popular theory was that United States servicemen brought four cougar kittens to Western Australia during World War II ; they eventually grew too big for captivity and were released — two at Fremantle and two at Bunbury .
 United States, Fremantle, Bunbury
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 United States, Fremantle, Bunbury