what's wrong with 'A' and 'B' ?
Let me answer your doubt
A certain medication used to treat migraine headaches acts by blocking pain receptors in the
brain. When a person takes the medication within one hour after ingesting grapefruit or
grapefruit juice, however, the effectiveness of the medication is significantly diminished.
Researchers have determined that the grapefruit contains a compound that alters the shape of
the pain receptors, with the result that the medication can no longer bind with them
completely. Which of the following conclusions could be most properly drawn from the
information given above?
A) If one takes the medication more than an hour after ingesting grapefruit, its effectiveness is
not diminished.We can keep this as an alternative, but in the paragraph only one case is covered, might be the juice has a longer effect, we know nothing about it
Also, when we compare this with D, D is the clear winner
b) Ingesting grapefruit after taking the medication does not diminish the effectiveness of the
medication.this cannot be said as the medicine might take some time in covering the receptors and before that the grape juice changes the shape of the receptors
c) There is only one type of pain receptor in the brain.No where connected
d) The medication is fully effective only when it properly binds with its target pain receptors.Correct, we can easily conclude that the medicine will not work, it the receptors are not fully covered.
e) It is not possible to design a medication for migraine headaches that can bond with the
altered receptors.not related to the subject
BCE can be easily removed, out of A and D, D is the clear winner
Hope it helps!
If this is an inference question, I agreed that D should be OA. However, this is a conclusion question, and B could not grasp the main idea of the premise. That "The medication is fully effective only when it properly binds with its target pain receptors" is more played that role of explanation why we should not take pills after grape juice than the main point what the premise is trying to convey.