Many people report that exposure to certain foods such as cheese, red wine, and chocolate, are associated with the onset of migraine headaches. other people report that exposure to certain smells (especially strong perfumes) seems to trigger a migraine headache, and some note that exposure to bright and flickering lights can be followed by a migraine. it would seem that a person with a tendency to get migraines should try to find which of these situations is associated with the onset of the headache and then avoid this stimulus.
all of the following, if true, would indicate potential problems with the recommendation above except
a. the time delay between the trigger and the onset of the headache can make it exceptionally difficult to identify the trigger.
b. the presence of a known trigger doesn�t always cause a migraine.
c. in many cases an internal hormonal change triggers a migraine.
d. in a high proportion of cases the patients report multiple triggers for their headaches.
e. most of the known triggers are common and almost unavoidable features of modern life.