Chinese carriers, boosted by drops in fuel costs, were the region’s most successful, with China Eastern Airlines, Hainan Airlines, Cathay Pacific Airways, China Southern Airlines and Xiamen Airlines all making it in the top 25 rankings.
Refer to the input text as context and select the correct relationship between 'Xiamen Airlines' and 'China Southern Airlines' from the available options.
Options: original broadcaster, distributed by, parent organization, location of formation