prep一题，怎么也想不明白

Although fullerenes--spherical molecules made entirely of carbon--were first found in the 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 are arranged in a previously unknown crystalline structure.

(E) Shungite itself is formed only under distinctive conditions.

为什么是D？哪位nn给点思路

题目说, F是最先在实验室发现的, 后来发现自然中的F, 实验室中的F是在特定条件下产生的

结论, 自然中的F, 可以帮助了解地壳情况

问削弱

D, 自然界中的F是一种未知的晶体结构

题目意思就是根据实验室中产生F的条件, 可以推出自然产生F的条件

而D说, 自然F是结构未知, 就是说其与实验室中的F结构不一样, 那么就不一定能推出自然产生F的条件, 所以削弱结论