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To continue offshore exploration  China  established the China National Offshore Oil Corporation (  CNOOC  ) to assist foreign oil companies in exploring developing extracting and marketing China's oil .
 country of headquarters: China, CNOOC
Given options, please tell me the relationships of all the listed entity pairs.Output format is "relation1: word1, word2; relation2: word3, word4". 
Option: cities of residence, top members employees, members, alternate names, origin, state or provinces of residence, title of person, spouse, city of headquarters, NA, founded by, state or province of headquarters, employee of, countries of residence, country of birth, founded, subsidiaries, country of headquarters 
Text: {0} 
 Entity Pairs:  China, CNOOC 
Answer:
 country of headquarters: China, CNOOC