Analyze the relationship between 'Halliburton' and 'HOUSTON' within the context of the input sentence.
Options: creator, headquarters location, distributed by, stock exchange

HOUSTON Aug 7 (Reuters) - Business is so tough for oilfield giants Schlumberger NV and Halliburton Co that they have come up with a new sales pitch for crude producers halting work in the worst downturn in years.
headquarters location