GMATPrep Verbal Question- Ancient hunter-gatherers

[LarryM989]

Doubt regarding a question in GMATPrep software :

Ancient hunter-gatherers developed instincts that stigmatized selfishness, and voluntary cooperation was encouraged as well, whether it be within the group or also with outsiders.

(A) selfishness, and voluntary cooperation was encouraged as well, whether it be within the group or
(B) selfishness, encouraging voluntary cooperation as well, both within the group but
(C) selfishness and also encouraging voluntary cooperation, within the group and
(D) selfishness and they encouraged voluntary cooperation, whether it be within the group or
(E) selfishness and encouraged voluntary cooperation, not only within the group but

The answer option here is E. This question is relatively easy as it has multiple errors in the answer options . We can solve this by looking at the usage of "Not only... but also" structure or the parallelism . However , i have a doubt regarding the parallel construction in the correct answer option E. Usually when "that + verb" is used in parallel construction, "that" should repeat after the word "and" .i.e in this case "that stigmatized selfishness " and "that encouraged voluntary cooperation " is the correct usage. However since the other options are worse when it comes to parallel construction i went with answer option E. Correct me if i am wrong. Or is the parallel construction between "Developed" and "encouraged"? Please clarify.

[Sage Pearce-Higgins]

Good job for analyzing problems even when you get them right. Correct answers, especially from GMATPrep, can teach us a lot about the kind of thing to expect on the test.

The parallel construction here is
[Ancient hunter-gatherers developed instincts that] (1) stigmatized selfishness and (2) encouraged voluntary cooperation

As you wrote, we could repeat the word 'that' (you'll often find that done on GMAT problems), but it's not essential. We'd usually repeat the small words if the mean was unclear. I honestly didn't consider the alternative parallel analysis that you implied, i.e.

[Ancient hunter-gatherers] (1) developed instincts that stigmatized selfishness and (2) encouraged voluntary cooperation

On reflection, this second interpretation is possible, but the parallel elements seem so uneven, and the meaning so wonky (simply two random facts about ancient hunter-gatherers, as opposed to the much more coherent meaning of the first interpretation) that I'd strongly favor the first way of reading the sentence. This isn't the only correct answer in which you can analyze the parallelism in more than one way. There's an old Official Guide problem that starts 'Joan of Arc, a young Frenchwoman' that has a similar issue.

[LarryM989]

Thank you very much for your prompt response !! I analyze answers on GMAT prep even after i get them right sometimes to know whether my approach is correct. I usually have seen the usage of "that "in parallel structures( both in the official guide and the Question pack) with the word "that" repeated after the word "and". Instinctively i started eliminating answer options without this structure and realized that none of the options match this logic. Hence i went for the other error on the usage of "not only ... but also" structure. Also the answer option E was better than the rest (except for the omission of that). My takeaway here is the usage of "that" after the word "and" is not essential in parallel construction.

[Sage Pearce-Higgins]

No need to quote my whole post. You're welcome: I'm glad to see you picking up takeaways and studying effectively.