Sentence Correction (SC) | Noted statistical consultant W. Edwards Deming, whose approa

Can somebody please answer these questions?

1. ------
Take away:
ESSENTIAL modifier + NO comma
NON-ESSENTIAL modifier + Commas
'THAT" is used for ESSENTIAL modifier only.
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Really? GMAT checks this?
Maybe somebody can also tell when does GMAT look at correct using of commas?

2. Will option E be correct if we remove comma before "that"?

E were revolutionary in post-war industrial practices in Japan, inspired several American management philosophies that included Total
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