"The princess will die, unless the hero saves her" would become either:
1) if the hero does not save her, then the princess will die, or
2) if the princess doesn't die, then the hero must have saved her
Both of these are correct translations! And notice, both are contrapositives of each other. They are logically equivalent statements.
Let's break this question down from the top and apply this! For main conclusion questions, it's best to begin with an understanding of the core in order to accurately identify which piece is the final conclusion. Here, we can distill the argument into these pieces:
COUNTERPOINT: We've made progress in computational sophistication
PREMISE: The present focus on computation will produce devices as intelligent as a human devoid of noncognitive responses.
CONCLUSION: Unless the focus is changed, AI research will fail to produce truly intelligent machines.
Depending on your preferred method of translating "unless", (B) is either the conclusion as stated or the contrapositive of it!
Not the Conclusion
(A) This is a perfect restatement of the premise. If you were trapped by this, apply the "therefore test" to the premise and conclusion.
(C) Nothing in the stimulus discusses the objectives of AI research.
(D) This connects the noncognitive abilities referred to in the premise to the determination of true intelligence, which appears in the conclusion. This is an assumption of the argument.
(E) This attempts to connect the same ideas as (D) does, but distorts the relationship.
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