Explanation

Reading the question: the subject matter of this prompt can be daunting. However, the structure of this prompt is not so forbidding; it's a brief argument, and in fact it resembles some of the other pseudo-syllogistic arguments that we have seen, even Drivers Over 30. So we can analyze the argument and build a filter using term matching, even if we don't fully understand all the terms involved.



The key term mismatch is in the second row of this table. Saying these conditions "never naturally occur on Earth" is not quite the same as saying that these conditions will never be observed. Maybe these conditions could occur artificially. It's not a physics point: term matching can help you identify logical leaps in an argument even if you don't understand all the terms involved. For example, since we note that the argument is consistent in referring to "quark-gluon plasmas" in the evidence and in the conclusion, we don't worry about the definition of that term.

Applying the filter: In the answer choices, (D) hits right on the answer. The other answer choices give facts that don't have anything to do with how the pieces of the argument are connected; for example, they don't discuss high temperature or density. Actually, (A) does, and (A) is next best after (D). But (A) leaves open whether quark stars exist or not and whether physicists can observe what's going on in them.

Logical proof: We can confirm our answer with the negation test. If high temperatures and densities not usually found on Earth could not be created in particle accelerators, that fact would strengthen the argument considerably: in that case, it would appear more likely that scientists can't observe this phenomenon. The correct answer is (D).