Glencore took a $US7.7 billion write-down in 2013 on the $US29 billion "merger" with Xstrata it executed the same year, with the bulk of that taken on goodwill.
Utilize the input text as a context reference, choose the right relationship between 'Xstrata' and 'Glencore' from the options.
Options: operator, distributed by, owned by, platform