To obtain information about Captain Hanson Gregory’s contribution to the doughnut, the most credible source when considering accuracy would be:
D. a published book, The Little Known Facts and Details of American Desserts.
A published book typically undergoes a more rigorous review process compared to websites or family webpages, which may not be as reliable. Additionally, a book on the subject is likely to provide a well-researched account of historical facts, making it a more credible source.