Because a manufacturer secures a patent for a pharmaceutical

[BTGmoderatorDC]

Because a manufacturer secures a patent for a pharmaceutical compound, the patent does not bar competitors from producing a chemical like it, as long as those chemicals have at least one structural difference with the patented compound.
(A) same as original
(B) That a manufacturer has secured a patent for one of its pharmaceutical compounds do not bar competitors from producing similar chemicals and having at least one important difference from the patented compound
(C) A patent for one of a manufacturer's pharmaceutical compounds does not bar competitors from producing a chemical like the patented compound, as long as the two differ structurally in at least one way
(D) When securing a patent for one of a manufacturer's pharmaceutical compounds, competitors are not barred from the production of chemicals such as the patented compound, provided that there is at least one structural difference
(E) Even if a manufacturer secures a patent for one of its pharmaceutical compounds, this does not bar competitors from the production of a chemical such as the patented compound, but having at least one structural difference from it

OA C

Source: Manhattan Prep

[deloitte247]

Option A: Incorrect
The innate conjunction used here is faulty, and does not follow parallelism.

Option B: Incorrect
In this option, there is a problem with the subject-verb connection. That is, between the Manufacturer and producing similar chemicals.

Option C: correct
This option follows parallelism in the right syntax and everything is in proper order. Pronoun and conjunctions were well placed.

Option D: Incorrect
such is not the right idiom to introduce a patent substance, it is faulty.

Option E: Incorrect
This suffers same fate as option D above and also, this option a faulty pronoun usage.