Question

What is the most likely reason Bismarck was named chancellor when King Wilhelm I became kaiser of Germany?

Wilhelm wanted to reward Bismarck, who was largely responsible for German unification.
Wilhelm did not want Bismarck to have as much power as he had when he was prime minister.
Wilhelm feared Bismarck would turn against Germany if he did not receive a position of power in the new government.
Wilhelm knew Bismarck was popular with both liberals and conservatives, which would help unite the empire.

Answer 1

Wilhelm wanted to reward Bismarck, who was largely responsible for German unification.

Bismarck was the architect of unification through his diplomacy and wars, so naming him chancellor both rewarded him and ensured continuity of leadership in the new empire.