Vatican city is considered an enclave because it is
a.
completely surrounded by rome, italy
b.
geographically separated from the mainland of italy
c.
a self-governing region within another state
d.
occupied by the roman catholic church

Vatican City is considered an enclave because it is completely surrounded by Rome, Italy.

Explanation:

The State of the Vatican City is a country in Europe. This is the territorial support of the Holy See enclosed in the Italian city and capital, Rome. In 2019, it has 799 inhabitants over a total area of 0.439 km2, making it the smallest state in the world.

The Vatican is an absolute monarchy, of divine and elective law led by the Roman Pontiff and bishop of Rome, that is, Pope Francis, elected March 13, 2013, following the renunciation of Benedict XVI, February 28 of the same year. The pope sovereignly exercises the triple executive, legislative and judicial power of the state.

doctrine that the us had the right to expand throughout north america.