Daniel is researching Molly Pitcher for a history project about the American Revolutionary War. He found a letter written by a soldier during the war. What can Daniel do to confirm the letter’s credibility? A. make sure there are no grammatical or spelling errors in the letter B. investigate the publishers of the letter and confirm their trustworthiness C. ensure the information in the letter answers the research question he formulated D. find other sources written by the same author to make sure he had extensive knowledge about the war