Nature of language

[greycellz]

1. Research during the past several decades on the nature of language and the processes that produce and make it understandable has revealed great complexity instead of underlying simplicity.

(A) that produce and make it understandable has revealed great complexity instead of underlying simplicity

(B) of producing and understanding it have revealed not underlying simplicity but great complexity

(C) by which it is produced and understood has revealed not underlying simplicity but great complexity

(D) by which it is produced and understood have revealed great complexity rather than underlying simplicity

(E) by which one produces and understands it have revealed great complexity instead of underlying simplicity

Guys, help me understand why the Official Answer is A and not C ?

[piyusht]

in C : its not sure wht does "it" signifies. Also process "that" is correct grammatically and fits better . E changes the meaning. C&D use IT hence can be ruled out.B doesnt fit as a sentence, hence A.

[viveksingh]

To me A sounds awkward. Only C sounds better. It definitely refers to language.
In A
Research ...on ..process that produce.... has revealed great complexity .
we need it after produce. produce what - language.

[piyusht]

it can also indicate "research" in C

[greycellz]

Don't you think there's a missing it in A ?

processes that produce (it) and make it

'processes that produce and make it' doesn't make sense..

[piyusht]

in my opinion Produce and Make refers to a single item, hence only one "it" is sufficient.

[comp_bos]

What do you guys think of this.

C. "revealed not underlying simplicity but great complexity"
A. "revealed great complexity instead of underlying simplicity"

Isnt C trying to invert the sentence for no good reason.

[greycellz]

in my opinion Produce and Make refers to a single item, hence only one "it" is sufficient.

The parallelism is broken. Ideally for such a construction when there's only one it, one should be able to break it in this form :
produce it understandable
make it understandable
The first one sounds incorrect

[greycellz]

What do you guys think of this.

C. "revealed not underlying simplicity but great complexity"
A. "revealed great complexity instead of underlying simplicity"

Isnt C trying to invert the sentence for no good reason.

It does that but it's not grammatically wrong.

[piyusht]

whts the Official Answer?