Answer:
After the troops of the Kingdom of Italy crushed the forces of the Papal States, is the right answer.
Step-by-step explanation:
The process of unification of Italy began in 1948 and ended in the year 1861 with the formation of the Kingdom of Italy. As Rome was under the occupation of the Papacy, Florence. For being the need of time, Florence was made provisional capital of the Kingdom of Italy. In the year 1870, the Italian forces entered Rome and defeated the forces of the Papal States and established Rome as the Capital of the Kingdom of Italy.