The Situation of Germany

"There is, in political geography, no Germany to speak of. There are Kingdoms and Grand Duchies, and Duchies and Principalities, inhabited by Germans, and each separately ruled by an independent sovereign with all the machinery of State. Yet there is a natural undercurrent tending to a national feeling and toward a union of the Germans into one great nation, ruled by one common head as a national unit. This feeling dates as far back into antiquity,,,when all the German tribes...united under him against the Roman invasion under VARRO [sic]. It culminated in the Christian era, after CHARLEMAGNE [sic]."

- The New York Times, July 1866
This source is BEST understood in the context of which 19th century movement?
A) Imperialism
B) Liberalism
C) Nationalism
D) Socialism