People who do regular volunteer work tend to live longer, on average, than people who do not. It has been found that ‘doing good,’ a category that certainly includes volunteer work, releases endorphins, the brain's natural opiates, which induce in people a feeling of well-being. Clearly, there is a connection: Regular releases of endorphins must in some way help to extend people's lives.


Which of the following, it true most seriously undermines the force of the evidence given as support for the hypothesis that endorphins promote longevity



The hypothesis is that there is a connection: Regular releases of endorphins must in some way help to extend people's lives.


If we need to weaken the argument, we need to say the otherwise- that there is no such connection.


Option D does just that. Only healthy and energetic people tend to do regular volunteer work- hence the longevity. Option D gives another reason for longevity.



(A) People who do regular volunteer work are only somewhat more likely than others to characterize the work they do for a living as "doing good."

 Not relevant to the hypothesis.  Eliminate


(B) Although extremely high levels of endorphins could be harmful to health, such levels are never reached as a result of the natural release of endorphins.

Not relevant to the hypothesis. Eliminate


(C) There are many people who have done some volunteer work but who do not do such work regularly.

The conclusion talks about regular releases of endorphins. People who don’t do regular exercise are beyond the scope of the argument. Eliminate.


(D) People tend not to become involved in regular volunteer work unless they are healthy and energetic, to begin with.


(E) Releases of endorphins are responsible for the sense of well-being experienced by many long-distance runners while running.


E- Releases of endorphins are responsible for the sense of well-being experienced by many long-distance runners while running.

- the conclusion is that- there is a connection: Regular releases of endorphins must in some way help to extend people's lives.
E is not relevant to the conclusion at all. 
Another serious flaw in option E is that sense of well-being cannot be equated with longevity. Eliminate

Option E says that endorphins are responsible for the sense of well-being. But does that lead to longevity? There's no data. 

Eliminate.