Based on an MOU concluded with PTT on information exchange and joint study regarding liquefied natural gas (LNG) as well as natural gas supply, Osaka Gas Group has for some years been stepping up cooperation with the PTT Group through operational and technical support for PTT’s LNG receiving terminal.
Refer to the input text as context and select the correct relationship between 'Osaka Gas' and 'liquefied natural gas' from the available options.
Options: founded by, product/material produced, currency, chairperson