A European doctor who worked in West Africa for two years reported that he never saw a case of appendicitis in the native African population. However, European personnel who came to work in the hospital sometimes developed appendicitis, as did their children, even those born and brought up in West Africa. The doctor also knew that Africans who immigrated to Europe sometimes developed appendicitis in Europe, at rates comparable to those for native Europeans.

What is the best explanation for the observations?

A) The climate of Europe is much more conducive to appendicitis than is that of West Africa.

B) There are genetic differences which make Europeans much more susceptible to appendicitis than Black Africans.

C) Because western-style medicine has been introduced into this part of Africa only recently, the indigenous population has long ago developed a natural resistance to appendicitis.

D) The very high temperatures in the African environment tend to suppress the bacteria which cause appendicitis.

E) Some feature of the common diet of Europeans, something not normally present in the diet of indigenous Africans, is conducive to appendicitis