Nature of Language

[gmat009]

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

I am totally confused between choices A and C. Can anyone tell me reason which one is correct and Why.

[stop@800]

IMO answer is A

research "have" is incorrect so BDE goes out

A language is not understood by a process rather a process make it understandable

Also in C
Not But is incorrectly used
not but is used for linguistically equivalent things

[wonder]

IMO answer is A

research "have" is incorrect so BDE goes out

A language is not understood by a process rather a process make it understandable

Also in C
Not But is incorrectly used
not but is used for linguistically equivalent things

i am still not quite sure about this. can someone pls explain? aren't great complexity and underlying simplicity. equivalent things?

[mastbombay]

Nice explanation.......but please let me know......why u said....not ...but is incorrectly used.......

can u pls explain in detail........about linguistically equivalent things....

IMO answer is A

research "have" is incorrect so BDE goes out

A language is not understood by a process rather a process make it understandable

Also in C
Not But is incorrectly used
not but is used for linguistically equivalent things

[stop@800]

copy pasting the standard examples

Pucci is not a Dog but a Cat.
Not Todd but Taka will study.

[NSNguyen]

(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

IMO: C
other acquice S- V agreement error