GMAT Sentence Correction (SC) | Re: Under high pressure and intense heat, graphite, the most

Under high pressure and intense heat, graphite, the most stable form of pure carbon, changes into the substance commonly referred to as diamond andremaining this way whether or not the heat and pressure are removed.

Issues:Parallelism | Meaning

Analysis:
1. In this sentence, we need to make sure that we maintain parallelism between verbs i.e. between "changes" and "remains" ("remaining" in original sentence)
(A) remaining this way whether or not
- not parallel
...

---