Why Did Otto I Select the City of Aachen for His

Why did Otto I select the city of Aachen for his coronation as emperor?

A) To lay claim to all the lands that Charlemagne had ruled from France to Eastern Europe
B) To clearly mark the creation of the Holy Roman Empire as a unified political system under his command
C) To demonstrate to the Viking raiders that he had no fear of their raids and he could protect his land even along the coast
D) To symbolize his intention to continue the tradition of Charlemagne and to demonstrate papal support for his rule