This is a question about people who have allergies to cats. We are asked to find the statement that is most strongly supported from the information above. Which means we have an Inference Question.
(1) People are allergic to the proteins found in the skin and saliva of cats.
(2) The particular protein responsible for the allergies varies from person to person
(3) All cats can provoke an allergic reaction
(4) However, some cats can cause an allergy in one person, but not in another person who is also allergic to cats.
(A) We can’t say that every person is allergic to some breeds but not others. Some people may be allergic to all breeds for all we know.
(B) One cat could cause an allergic reaction in all allergy suffers. Nothing in the stimulus forbids that. Part (4) of the analysis doesn’t mean that all cats affect some but not all people.
(C) Correct! “Not all cats have identical proteins in their skin and saliva” — The reason this has to be true is — if all cats had identical proteins then it wouldn’t matter which protein a given person was allergic too, because all cats have the same proteins (lets call them X, Y, Z). Then it wouldn’t matter if person A is allergic to X and person B is only allergic to Y, they would both be always allergic to the same/all cats. This would violate the rule set out in Analysis (4).
Therefore, if cats have different proteins then this could explain why a person may be allergic to Cat C but not allergic to Cat D.
(D) We do not know anything about the intensity of the people with allergies…
(E) May sound tempting… but the stimulus tells us nothing about how hard or easy it may be to predict which cats will cause an allergic reaction in which person.