see the words “a history the city did not truly” here the history is referring towards " twelfth-century cathedral, fifteenth-century palace" → Now, look at the wording “sought to legitimize” → this hint that what the architects are telling may not be true(They’re making stuff up! ). Now, if we go back to “a history the city did not truly” , we can now see that they’re making stuff up thus, “a history the city did not truly__have/possess__”
Question 5:
See how they’re contrasting “each outcome” → single vs “any outcome” → many(Contrast signal word->Yet)
So, before the semi-colon we have our blank(i) and it’s easy to fill as the wording “just one____ among million” → thus one possibility/chance/happening all make good guesses.
For blank(ii) we’re saying it’s not accidental(or random) and we can logically interpreted it! thus, rational make much sense!
A is too strong as you yourself earlier quoted “either limit or decrease the value of “learning.” thus, you can’t totally replace learning → which superseded implies!
Now, we’re left with D and E
look at clue for blank 2 "as the most instinctive of the behavioral responses " → so we’re looking for an idea that say it’s most natural or inherent → thus, stereotyped makes much more sense then inventive!
Also, Greg has done the whole walkthrough of big book :https://www.gregmat.com/course/old-gre-walkthroughs