You didn't include the map, so I can't be entirely sure, but if it's the same test that I have, it's B.
The reunification of German was through force during the reign of Bismarck. The first war of unification was the Danish War in 1862. This was followed by the Austro-Prussian war in 1866. In the end, Bismarck used the Franco-Prussian war of 1870-71 to unify the states of north Germany
This was another answer from another person who asked it hopefully this helps or soemthing