Information: - The Roman Empire (Koine and Medieval Greek: , tr. ) was the post-Roman Republic period of the ancient Roman civilization, characterized by government headed by emperors and large territorial holdings around the Mediterranean Sea in Europe, Africa and Asia. The city of Rome was the largest city in the world BC AD, with Constantinople (New Rome) becoming the largest around 500 AD, and the Empire's populace grew to an estimated 50 to 90million inhabitants (roughly 20% of the world's population at the time). The 500-year-old republic which preceded it was severely destabilized in a series of civil wars and political conflict, during which Julius Caesar was appointed as perpetual dictator and then assassinated in 44 BC. Civil wars and executions continued, culminating in the victory of Octavian, Caesar's adopted son, over Mark Antony and Cleopatra at the Battle of Actium in 31 BC and the annexation of Egypt. Octavian's power was then unassailable and in 27 BC the Roman Senate formally granted him overarching power and the new title "Augustus", effectively marking the end of the Roman Republic. - The European Union (EU) is a political and economic union of member states that are located primarily in Europe. It has an area of , and an estimated population of over 510 million. The EU has developed an internal single market through a standardised system of laws that apply in all member states. EU policies aim to ensure the free movement of people, goods, services, and capital within the internal market, enact legislation in justice and home affairs, and maintain common policies on trade, agriculture, fisheries, and regional development. Within the Schengen Area, passport controls have been abolished. A monetary union was established in 1999 and came into full force in 2002, and is composed of 19 EU member states which use the euro currency. - Rocca di Cave is a comune ( municipality ) in the Province of Rome in the Italian region Latium , located about 40 kilometres ( 25 miles ) east of Rome . It is home to the remains of the Colonna family 's castle , which today houses a Geo - Palaeontological Museum and an astronomical observation point . - Latium is the region of central western Italy in which the city of Rome was founded and grew to be the capital city of the Roman Empire. Latium was originally a small triangle of fertile, volcanic soil on which resided the tribe of the Latins or Latians. It was located on the left bank (east and south) of the Tiber river, extending northward to the Anio river (a left-bank tributary of the Tiber) and southeastward to the Pomptina Palus (Pontine Marshes, now the Pontine Fields) as far south as the Circeian promontory. The right bank of the Tiber was occupied by the Etruscan city of Veii, and the other borders were occupied by Italic tribes. Subsequently, Rome defeated Veii and then its Italic neighbors, expanding Latium to the Apennine Mountains in the northeast and to the opposite end of the marsh in the southeast. The modern descendant, the Italian "Regione" of Lazio, also called "Latium" in Latin, and occasionally in modern English, is somewhat larger still, but not as much as double the original Latium. - Rome is a city and special "comune" (named "Roma Capitale") in Italy. Rome is the capital of Italy and of the Lazio region. With 2,870,336 residents in , it is also the country's largest and most populated "comune" and fourth-most populous city in the European Union by population within city limits. The Metropolitan City of Rome has a population of 4.3million residents. The city is located in the central-western portion of the Italian Peninsula, within Lazio (Latium), along the shores of Tiber river. The Vatican City is an independent country geographically located within the city boundaries of Rome, the only existing example of a country within a city: for this reason Rome has been often defined as capital of two states. After reading the paragraphs above, we are interested in knowing the entity with which 'rocca di cave' exhibits the relationship of 'currency'. Find the answer from the choices below. Choices: - euro - mark
A:
euro