Take context from the input text and decide on the accurate relationship between 'BG Group' and 'Royal Dutch Shell' from the options provided.
Options: parent organization, platform, chairperson, position held

Oil producers decline Oil producers, including Royal Dutch Shell (Xetra: R6C1.DE - news ) and BG Group (LSE: BG.L - news ) , headed south as Brent crude hovered just under $49 per barrel, the lowest level since January.
parent organization