Sentence Correction

The voluminous personal papers of Thomas Alva Edison reveal that his inventions typically sprang to life not in a flash of inspiration but evolved slowly from previous works.
(A) sprang to life not in a flash of inspiration but evolved slowly
(B) sprang to life not in a flash of inspiration but were slowly evolved
(C) did not spring to life in a flash of inspiration but evolved slowly
(D) did not spring to life in a flash of inspiration but had slowly evolved
(E) did not spring to life in a flash of inspiration but they were slowly evolved.

Answer is C

My Question:

According to the answer guide, the reason C is the right answer b/c "spring" is parallel to "evolved." "Spring" is in the infinitive and "evolved" is in the past tense, so why can it be in parallel? I understand in the idiomatic structure, Not X...But...Y, X and Y must be parallel. So...two elements can be parallel even if they are in different tenses?

My second question is "had slowly evolved" in D. I guess logically "had slowly evolved" makes sense here (Since the inventions evolve from a much earlier time period to an earlier time period), but is the reason it is wrong here b/c we need to preserve the parallelism of Not..X...But Y?

Thanks!

Hi,
'did not spring' is parallel to 'evolved'. 'did not spring' is simple past, 'do/does not spring' is simple present. Hope, this answers your query.

Cheers!

Past perfect is used only when two things happen at different times in the past. But, in this case there is no such thing. Hence, simple past is sufficient.

Here is another question in which the use of past perfect has been advocated by Mitch GmatGuru nY
https://www.beatthegmat.com/og12-sequenc ... tml#365642
Why the use of past perfect not required in this question
The Papers tell us about an action that took place before the papers were written

Thanks for the tips everyone! They were most helpful!