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 interests

E.        the number of white blood cells will increase radically if behavior is consistently magnanimous

Reference:

In my view, the reasoning in this argument is that:

magnanimous behaviorà beneficial chemicals produced by the brainà they activity of these white blood cellsà fight infection

So, the correct answer is D.

A is out of scope. Because unselfish motives is not mentioned in this argument.

B and C have the same mistake. From the above reasoning , it is clear that because of magnanimous behavior, some beneficial chemicals were produced by the brain. But the statement of B and C fail to convince us that magnanimous behavior can be regulated by the presence of absence of certain chemicals in the brain.

E is out of scope. The argument fails to establish the casual relationship between the number of white blood and the rate of magnanimous behavior.