Why didn’t popes leave the Vatican for more than 50 years after 1870?

Here is the question :

WHY DIDN’T POPES LEAVE THE VATICAN FOR MORE THAN 50 YEARS AFTER 1870?

Here is the option for the question :

Was a warrant for their arrest
A territorial dispute with Italy
They chose to be hermits
The Swiss Guard went on strike

The Answer:

And, the answer for the the question is :

A territorial dispute with Italy

Explanation:

[STC009769]. Pope Pius IX walled himself within the Vatican during the Italian reunification in 1870 and refused to leave out of protest because he thought it would be seen as endorsing the new secular authority in Italy. Until 1929, when the modern state of Vatican City was founded and formally separated from Italy, his successors carried on the protest.