The mind and the immune system have been shown to be intimately linked, and scientists are consistently finding that doing good deeds benefits one’s immune system. The bone marrow and spleen, which produce the white blood cells needed to fight infection, are both connected by neural pathways to the brain. Recent research as shown that they activity of these white blood cells is stimulated by beneficial chemicals produced by the brain as a result of magnanimous behavior.
The statements above, if true, support the view that
(A) good deeds must be based on unselfish motives lack of magnanimity is the cause of most serious illnesses.
(B) magnanimous behavior can be regulated by the presence of absence of certain chemicals in the brain.
(C) magnanimous behavior can be regulated by the presence or absence of certain chemicals in the brain.
(D) magnanimity is beneficial to one’s own interhests
(E) the number of white blood cells will increase radically if behavior is consistently magnanimous
答案是D 请问是怎么推出來的呢?! 怎么不选E呢?? | 
