The correct answer is C) a quote of Hitler's announcement, D) the reaction of Jewish business owners, and E) the types of business he boycotted.
The details that would provide helpful factual support for this sentence are a quote of Hitler's announcement, the reaction of Jewish business owners, and the types of business he boycotted.
The sentence was: "Hitler announced a boycott of Jewish-owned businesses."
So it would be very important to have a direct quote from Hitler, stating the reason why he made that decision. Another aspect is the type of business the decision affected and how impacted to the Jewish people. Finally, another important aspect would be to know the first impressions and opinions of the affected, in this case, the Jewish people that owned the business, because with this we can know the other side of the story.
