Bunuel
Plant oils
do not represent a new attempt to replace fossil fuels; it was already made by Rudolf Diesel in 1912.
(A) do not represent a new attempt to replace fossil fuels; it
(B) are not a new attempt to replace fossil fuels; the same one
(C) represent not a new attempt to replace fossil fuels, but one that
(D) are not a new attempt to replace fossil fuels, but one that
(E) are not new as an attempt to replace fossil fuels; it
Key decision maker:Meaning: Plant oils are a new attempt or Plant oils represent a new attempt.
Clearly, plant oils themselves are not an attempt. Meaning conveyed is nonsensical. Therefore, we can eliminate option B, D and E.
A -
antecedent of "it" ambiguous - does "it" modify fossil fuels, a new attempt or Plant oils? Incorrect.
C - (1)
Parallelism: Plant oils represent...(a) not only a new attempt...(b) but also represent one that was already made. Structure is correct, (2)
One - Here one clearly refers to "attempt", (3)
That - Because the sentence has "one", that correctly modifies "one = attempt". The sentence also conveys intended meaning. Structure ✓ Meaning ✓.
Therefore,
option C is the correct answer. Posted from my mobile device