The human nervous system and a telephone system

[mikrodj]

The human nervous system and a telephone system superficially resemble each other, not only because the former carries information in the form of electrical impulses and because all of its neural pathways converge in the brain and spinal cord, which together form a kind of central exchange.

(A) The human nervous system and a telephone system superficially resemble each other, not only because the former carries
(B) The human nervous system and a telephone system bear a superficial resemblance because they both carry
(C) The human nervous system bears a superficial resemblance to a telephone system both because the former carries
(D) Superficially, a telephone system resembles the human nervous system both because they carry
(E) There is a superficial resemblance between a telephone system and the human nervous system, not only because they both carry

GMAT Prep question
OA C

Is the problem with D the placement of superficially, the ambiguity of its, or both?
Is the pronoun they correctly used in option D?

Thank you in advance

[sam.railkar]

The human nervous system and a telephone system superficially resemble each other, not only because the former carries information in the form of electrical impulses and because all of its neural pathways converge in the brain and spinal cord, which together form a kind of central exchange.

(A) The human nervous system and a telephone system superficially resemble each other, not only because the former carries
(B) The human nervous system and a telephone system bear a superficial resemblance because they both carry
(C) The human nervous system bears a superficial resemblance to a telephone system both because the former carries
(D) Superficially, a telephone system resembles the human nervous system both because they carry
(E) There is a superficial resemblance between a telephone system and the human nervous system, not only because they both carry

GMAT Prep question
OA C

Is the problem with D the placement of superficially, the ambiguity of its, or both?
Is the pronoun they correctly used in option D?

Thank you in advance

The non-underlined portion of the sentence has "because all of its (singular). So the earlier portion cannot have they. It should refer to something singular. C correctly identifies one of those 2.

[RonPurewal]

see here

gmat-prep-sc-help-t2567.html

[pujad303]

Why A is wrong?

[Sage Pearce-Higgins]

The words 'not only...' begin a parallel construction that needs to be continued with 'but also...'.