It is D because you have a match with the question.
A - Efforts are not immensely characteristical for that period, there were no efforts.
B - Definition of itelligence did not attract some attention, it attracted huge attention-a surge og interests.
C - It was not a desire to broaden the definition, it came by 1980s.
E - The desire was not to narrow the definition. On contrary-to expand it.
D is therefore correct - Ii WERE radical new definitions, they indeed came suddenly and unexpectedly into being.
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