Final answer:
The two countries incorporated into the Russian Empire as Grand Duchies after the Napoleonic Wars were Finland and Poland, solidifying Russia's status as a major power in Europe.
Step-by-step explanation:
After the Napoleonic Wars, two countries were incorporated into the Russian Empire as Grand Duchies. The correct answer to the question is a. Finland and Poland. These areas were strategically important for Russia, and their incorporation helped to solidify its status as a major European power after the defeat of Napoleon. Sweden, having lost Finland to Russia in an earlier conflict, was compensated by gaining territory from Denmark, and Prussia expanded by acquiring parts of Saxony and other Germanic states. The territorial adjustments following the Napoleonic Wars were significant, and they reshaped much of the European landscape during that time.