Answer:
The Kingdom of Sardinia took the lead in the C. unification of Italy into one monarchy.
Step-by-step explanation:
Italy had always been a country separated into various states and following the French invasion under Napoleon's influence, Italian peninsula had different leadership. Some parts of Italy were ruled by Napoleon himself, while others were under his brother then his brother-in-law's leadership. The downfall of Napoleon forced for reconstitution.
Ideas to unite the country emerged and became secretly popular. As the nationalism movement gained momentum, various societies were formed whose ulterior motives was to overthrow the Austrian rule which failed the first time. The Sardinia Kingdom made an alliance with French people which finally led to Austria defeat and gave rise unification.