Critical Reasoning

This question appeared on my GMAT practice test. Even after I saw the answer, I could not comprehend the reason.

Question :

Although fullerenes - spherical molecules made entirely of carbon - were first found in laboratory, they have since been found in nature, formed in fissures of the rare mineral shungite. Since laboratory synthesis of fullerenes requires distinctive conditions of temperature and pressure, this discovery should give geologists a test case for evaluating hypotheses about the state of the Earth's crust at the time these naturally occurring fullerenes were formed.

Which of the following, if true, most seriously undermines the argument ?

A) Confirming that the shungite genuinely contained fullerenes took careful experimentation.
B) Some fullerenes have also been found on the remains of a small meteorite that collided with a spacecraft.
C) The mineral shungite itself contains large amounts of carbon, from which the fullerenes apparently formed.
D) The naturally occurring fullerenes arranged in a previously unknown crystalline structure.
E) Shungite itself is formed only under distinct conditions.

Found it on an earlier discussion.
Great explanation..!!


The passage is basically trying to arrive at conclusion with respect to hypotheses about the state of the Earth's crust in the past. The assumption here is that both laboratory grown fullerenes and naturally occurring fullerenes are similar and, since laboratory synthesis of fullerenes requires distinctive conditions of temperature and pressure, geologists can assume that similar conditions must be needed for naturally occurring fullerenes to grow. Based on this principle the passage suggests that geologists should evaluate their hypotheses.

One way to undermine this argument is to undermine the very basic assumption that both laboratory grown fullerenes and naturally occurring fullerenes are similar. If both laboratory grown fullerenes and naturally occurring fullerenes are different, then it possible that both require different conditions to grow and if this is true, then the principle on which the passage suggests the geologists should test the hypotheses doesn't seem helpful.

Option D does the same job I just explained above. D says that the naturally occurring fullerenes are arranged in a previously unknown crystalline structure. So we can safely infer that both laboratory grown fullerenes and naturally grown fullerenes are different because if they were same, then geologists would have been aware of this unknown crystalline structure.