For ‘find a conclusion’ based questions, the correct conclusion can only be supported by the facts stated in the question, not other assumptions (no matter how obvious) can be added.
a) The argument makes no mention of whether or not countries are excluded from the international market. Eliminate.
b) This is exactly the opposite of what the argument is saying. Be careful, because all the elements of the conclusion are mentioned in the argument which makes it attractive, but the argument actually opposes the conclusion. Eliminate
c) Correct, the argument accounts for the effect that international oil fluctations have on domestic prices, and accounts for the fact that domestic oil is sold domestically.
d) Again, this conclusion contradict what the argument is saying. Eliminate
e) This conclusion references behaviours (importing) that is not present in the argument.
What is the source for this question? I think GMAT type questions tend to conform to the ‘absolutely no assumptions allowed’ rule a bit more than this one did.
In the study cave!