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.
b) Ingesting grapefruit after taking the medication does not diminish the effectiveness of the
medication.
c) There is only one type of pain receptor in the brain.
d) The medication is fully effective only when it properly binds with its target pain receptors.
e) It is not possible to design a medication for migraine headaches that can bond with the
altered receptors



D