What is the relationship between 'BG Group' and 'Royal Dutch Shell' in the context of the input sentence.
Options: chief executive officer, parent organization, stock exchange, member of

Merger and acquisition activity in the energy sector has been rekindled as company valuations slumped along with oil prices, highlighted by Royal Dutch Shell (Xetra: R6C1.DE - news ) 's $70 billion bid to acquire BG Group (LSE: BG.L - news ) earlier this year.
parent organization