American Heart Association researchers have calculated that

[abhisheks901]

American Heart Association researchers have calculated that one person in the United States should experience a coronary event every 26 seconds.
(A) one person in the United States should experience a coronary event every 26 seconds
(B) a person in the United States should experience a coronary event once in every 26 seconds
(C) a coronary event will strike one person in the United States once in every 26 seconds
(D) every 26 seconds a person in the United States will experience a coronary event
(E) every 26 seconds a person in the United States should experience a coronary event

My query:
i want to understand the meaning and differences between should, ought to and will.
how can we be so sure that a person will experience a coronary event. whereas, should suggests that according to the circumstances prevailing, there is a high chance that a person should experience a coronary event.


Thanks

[Sage Pearce-Higgins]

On the GMAT, 'should' usually indicates moral obligation (check out p26 of the SC strategy guide). Remember that the word 'will' is still a prediction - no statement about the future is completely certain.