Question

Which best describes the authors’ purpose in using a quotation from Adam Smith’s book The Theory of Moral Sentiments? to highlight their knowledge of Scottish philosophers to prove that people are inherently dishonest to demonstrate that incentive is the driving force behind cheating to lend credibility and additional support to their conclusion

Answer 1

The correct answer should be
to lend credibility and additional support to their conclusion

Quoting famous books is usually done to support what you're saying, it's not about proving things or demonstrating it, it's rather to help make your hypothesis seem more legitimate. Highlighting your knowledge is not necessary and sounds a bit arrogant.

Answer 2

answer is D, you're welcome