Utilize the input text as a context reference, choose the right relationship between 'Rosneft' and 'Petroleum' from the options.
Options: member of, product/material produced, parent organization, publisher

On the supply side, recent speculation that Russia might be willing to cooperate with the Organization of the Petroleum Exporting Countries (OPEC) to curb output in support of prices was given a blow on Monday after the chief executive of Russian oil major Rosneft ruled out a Russian cut.
product/material produced