Please answer the following question: Retail therapy has long been considered as a good way to let off stress. Now, US scientists have discovered not only does retail therapy exist,but that it could be caused by an individual's fear of sudden death. Researchers found materialistic people thought terrorism and war more stressful than others. Psychologists believe the rise of materialism around the world and its treatment effect on extreme stress might be a response to fear of death caused by acts of terrorism, disease and natural disasters. The scientists from Michigan State University said people with possession obsessions often have lower self-esteem than others so are more likely to shop as the result of severe psychological suffering. Ayalla Ruvio,a business professor studying people's shopping habits while rockets fell in Israel, said, "When the going gets tough, the materialistic people go shopping. This stress spending is likely to produce even greater stress and lower well-being. Essentially, materialism appears to make bad events even worse. Dr Ruvio led a two-part study of Israeli citizens living in a town that came under extreme rocket attacks for about six months in 2007. She compared 139 residents of the southern town with 170 from another town that was not under attack to see how their symptoms of post-traumatic stress and shopping habits varied. Dr Ruvio found that, when faced with a deadly threat, those who are highly materialistic suffered much higher levels of stress,while their tendency to shop was increased. Dr Ruvio said, "The relationship between materialism and stress may be more harmful than commonly thought." The second stage of their research surveyed 855 Americans about their materialistic nature and fear of death. They found shopping was used to relieve feelings of stress and anxiety about death but this was in response to fear of a variety of life-threatening events like car accidents, criminal attacks and natural disasters. Why did Dr Ruvio choose to study the two groups of Israeli citizens mentioned in the passage? A) They enjoy the special shopping culture. B) The stresses they face are usually deadly. C) They are in different situation in terms of war. D) They are usually active participants for researchers.
A:
C