Answer:
Option D, a research paper published in an academic journal and an approved PhD dissertation
Explanation:
Nicholas must present her discovery with back up of strong literature review. This literature review must include papers published in good journals and only approved research dissertation.
An internet blog, news article and college level textbook are not considered as an approved study. These are not reviewed or approved by any peer group or associations.
Good papers of any good journals are reviewed and examined thoroughly by the peers and thus they can be used as a backup of any study.
Hence, option D is correct
