Answer:
B. environmental, rivalry
Step-by-step explanation:
Delta Airlines recently touted its inclusion on the prestigious Dow Jones Sustainability Index, a financial index aimed at recognizing environmental leaders within industries. Such an event is an example of how the changing environmental preferences of consumers can alter the threat of rivalry among existing industry incumbents. Due to the call for sustainable environmental practices, businesses are becoming more environmental conscious and becoming more environmental friendly in their practices, this new consciousness and change in business practices could alter the competition and rivalry among existing industry incumbents as they will all want to shift their practices to support sustainability.