What is the relationship between 'Rosneft' and 'Petroleum' in the context of the input sentence.
Options: parent organization, member of, product/material produced, 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