Let's clarify each option:
(A) growing area, rather than being the active, flowering stage of the plant’s reproductive cycle, would be the inactive, dormant stage.
This option conveys the intended meaning, but it is slightly wordy. The phrase "rather than being" can be simplified.
(B) growing area is not the active, flowering stage of the plant’s reproductive cycle but the inactive, dormant stage.
This option introduces a negative assertion, saying "is not," which changes the meaning. The original sentence is focused on what is favorable, not on what it is not.
(C) growing area is the inactive, dormant stage of the plant’s reproductive cycle rather than the active, flowering stage.
This option correctly conveys the intended meaning in a clear and concise manner. It is a good choice.
(D) growing area, instead of being the active, flowering stage of the plant’s reproductive cycle, would be the inactive, dormant stage.
This option is similar to (A) but avoids the slight wordiness by using "instead of being," but still option C seems more clear
(E) growing area is, instead of the active, flowering stage of the plant’s reproductive cycle, rather the inactive, dormant stage.
This option is verbose and somewhat awkward. The use of "is" and "rather" together makes the sentence less concise.
In summary, options (C) is more concise, making it a preferable choice.