Sentence Correction

Neuroscientists distinguish organic amnesia, which has some physical cause such as an occurrence of blunt force trauma to the head, from psychogenic amnesia, which is purely psychological in origin.

A organic amnesia, which has some physical cause such as an occurrence of blunt force trauma to the head, from psychogenic amnesia, which is purely psychological in origin
B organic amnesia from psychogenic amnesia, the first of which has some physical cause such as an occurrence of blunt force trauma to the head, and the second of which is purely psychological in origin
C between organic amnesia, in which they have experienced some physical cause such as an occurrence of blunt force trauma to the head, and psychogenic amnesia, which is purely psychological in origin
D between organic amnesia, which has some physical cause such as an occurrence of blunt force trauma to the head, and psychogenic amnesia, which is purely psychological in origin
E between organic amnesia, in which some physical cause exists such as an occurrence of blunt force trauma to the head, and psychogenic amnesia, which is purely psychological in origin

my concern: i find the usage of "such as" wrong in all the choices. Also why should be we choose D over A?

The SC above is modeled after SC107 in the OG11:
https://www.beatthegmat.com/dr-frosh-t53068.html

The explanation in the OG11 states the following:
This sentence contrasts two problems, and it must use the correct idiomatic expression to do so effectively: between x and y.
Given this explanation, we must consider in the SC posted above D a better option than A.

That said, I would ignore both the SC posted above and SC107 in the OG11.
SC107 is so old as to be irrelevant to the modern GMAT.
The modern GMAT does not test such idiomatic subtleties.

thanks Guru
kindly also tell me whether us usage of "such as" is right in this SC. i feel "such as" should always be preceded by "plural noun" and not singular noun

aditya8062 wrote:thanks Guru
kindly also tell me whether us usage of "such as" is right in this SC. i feel "such as" should always be preceded by "plural noun" and not singular noun

Both singular and plural nouns are fine. Here are two examples from the Chicago Manual of Style, a source the GMAC would respect.

Both singular and plural nouns are fine. Here are two examples from the Chicago Manual of Style, a source the GMAC would respect.

OK but incidently no prep question has violated this rule of "such as" . Also i feel that it very logical to always have a plural noun before "such as" because "such as" introduces a "partial list" of examples from a "lot" of many examples. will it be prudent to change my perception?