You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Category: SUBWAY STOPS 
Clue: You can ride one line in this world capital from Kifissia to Pireas
athens

Category: DOUBLE TALK 
Clue: In the 1920s Donald Duncan introduced this child's toy to America & it's had its ups & downs ever since
yo-yo

Category: TAIPEI PERSONALITY 
Clue: He was driven into exile in Taiwan in 1949; today his name is on the international airport in Taipei

chiang kai-shek