The answer is the Caspian sea separates Asia and Europe.
C is correct, the charter is an unwritten but binding document
I think it is the first one
An enclave is a territory or country with boundaries that are completely within the boundaries of another country. Lesotho is a common example, as it is completely surrounded by South Africa. An exclave is a portion of a country that is separated geographically from the country's mainland. Gibraltar, located on Spain's coast, is an exclave of the United Kingdom. Kaliningrad is an exclave of Russia.