Final answer:
The correct sequence is Napoleon's defeat, followed by the Congress of Vienna, and then German Unification, corresponding to option (a).
Step-by-step explanation:
The correct order of the events you've listed is as follows: Defeat of Napoleon, Congress of Vienna, and German Unification. Specifically, Napoleon's defeat occurred initially in 1814 and ultimately at the Battle of Waterloo in 1815. Following this, the Congress of Vienna was convened, beginning in November 1814 and concluding in June 1815. This congress aimed to restore the balance of power and reshape Europe after the Napoleonic Wars. The German Unification took place later, culminating in 1871 under the leadership of Otto von Bismarck, Chancellor of Prussia. Therefore, the correct order of these events would be option (a): Defeat of Napoleon, Congress of Vienna, German Unification.