The mind and the immune system have been shown to be intimately linked

Going to start off my thought process with stating that I was a bit confused by the tag to this question... In my attempts to practice must be true questions I came across this question. I believe this question is more of a main point must-be-true-hybrid more so than a traditional must be true question... If anyone else agrees/disagrees let me know.

Stimulus:
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 has shown that the activity of these white blood cells is stimulated by beneficial chemicals produced by the brain as a result of magnanimous behavior.

Question Stem: The statements above, if true, support the view that - i interpreted this as a main point, where I would be searching for a must be true answer choice that illustrated the author's conclusion/main point

(A) good deeds must be based on unselfish motives
Sure the word magnanimous is an antonym to selfish (so synonym to selfish), but because nothing in the stimulus hints at tying unselfish motives to good deeds to the extreme that this answer choice does "must be based on," this answer choice is wrong. The stimulus states that: "scientists are consistently FINDING that"

(B) lack of magnanimity is the cause of most serious illnesses
This is also not stated by the stimulus, that the "opposite" of: "research has shown...activity...beneficial chemicals...result of magnanimous behavior," is true. This could be true, but seems extreme to suggest causation, which is not done in the stimulus

(C) magnanimous behavior can be regulated by the presence or absence of certain chemicals in the brain
I was confused with this one and didn't mark this answer choice as a "loser" right away... but reading the choice again I interpreted this as the magnanimous behavior can be impacted/affected by the chemicals in the brain, which seems to be a mistaken reversal type answer choice. The stimulus states that the white blood cells are stimulus by chemicals that are produced as a result of the behavior...not that the behavior is regulated by the chemicals..

(D) magnanimity is beneficial to one’s own interests
This answer choice wasn't fully clear to me as the confusion of whether this question is a must be true problem vs. main point problem still biased my view...however, i believe this is the correct answer choice as one can deduce or infer from the stimulus that this answer choice is true and accurately captures the author's main point.

(E) the number of white blood cells will increase radically if behavior is consistently magnanimous
This is not mentioned in the stimulus, cant infer that they will increase rapidly..

Apologies if any of my explanations have any grammatical errors or run-on sentences. I am trying to capture my thought process as clearly as possible.

Cheers.