Refer to the input text as context and select the correct relationship between 'DESFA' and 'gas' from the available options.
Options: product/material produced, developer, subsidiary, founded by

-- SOCAR, Azerbaijan's state energy company, to buy stakes in Greek natural gas grid operator DESFA from Greek natural gas utility DEPA (notified Oct (HKSE: 3366-OL.HK - news ) .
product/material produced