question 9 is based on the following graph
9.which of the following， if true， contributes most to
an explanation of the change in ice cream sales？
（a）because of low demand for its transcontinental
flights departing from the airport， one airline
ceased offering such flights as of december
31，1993.
（b）there were fewer airline passengers who were
traveling to destinations outside the united
states in january1993 than there were in
january1992
（c）the average daily number of passengers at the
airport in the month of january was the same
for each of the three years
（d）in january 1993 a blizzard forced all flights out
of the airport to be canceled for three days，
stranding many passengers at the airport.
（e）there were five percent fewer commuter flights
scheduled to depart from the airport in january
1993 than there were in january of either 1991
or 1992
10.people whose bodies cannot produce the substance
cytochrome p450 are three times as likely to develop
parkinson's disease， a disease that affects the brain，
as are people whose bodies do produce this substance.
since cytochrome p450 protects the brain from toxic
chemicals， toxic chemicals probably play a role in the
development of parkinson's disease.
which of the following， if true， most strongly
supports the argument？
（a）it will soon be possible for cytochrome p450 to
be synthesized for the treatment of people
whose bodies cannot produce this substance.
（b）many people whose bodies are unable to
produce cytochrome p450 lack the ability to
produce certain other substances as well.
（c）cytochrome p450 has no effect on the brain
other than to protect it from toxic chemicals.
（d）people with parkinson's disease often exhibit a
marked lessening in the severity of their symp-
toms when they are treated with dopamine， a
chemical produced naturally in the brain.
（e）many people with parkinson's disease have the
ability to produce cytochrome p450 naturally.