Question: What was the nationality of the person Jansen was named after?
Context: Beketov is a small lunar crater that lies in the northern reaches of the Mare Tranquillitatis and is named after Nikolay Beketov.  To the south is the ghost crater Jansen R. Northeast of Beketov, along the edge of the mare, is the crater Vitruvius located about 53 km.  Beketov was previously designated Jansen C before being named by the IAU.  The flooded crater Jansen itself lies nearly 70 km to the south.  Other nearby large craters are Dawes located about 75 km west and Fabbroni to the north. A British protected person (BPP) is a member of a class of certain persons under the British Nationality Act 1981 associated with former protected states, protectorates, mandated and trust territories under British control.  The inhabitants of these former states or territories were never automatically entitled because of their birthplace to become British subjects or citizens, but were given the status of British protected person instead.  (A few of those born in such areas might have other claims to British nationality; for example, one based on the status of their parents.) Jansen is a lunar crater in the north part of the Mare Tranquillitatis, named after Zacharias Janssen.  It is located to the east-southeast of the crater Plinius.  The rim of Jansen is low and narrow, with a notch along the western edge.  The interior is relatively level, which may indicate it has been covered by lava.  To the south-southwest a small but prominent crater lies on the crater floor, halfway between the center and the rim, further southeast is a small but prominent crater named Sinas. Zacharias Janssen (also Zacharias Jansen or Sacharias Jansen) (1585 – pre-1632) was a Dutch spectacle-maker from Middelburg associated with the invention of the first optical telescope.  Janssen is sometimes also credited for inventing the first truly compound microscope.  However, the origin of the microscope, just like the origin of the telescope, is a matter of debate. Venezuelan nationality law is based on the principle of Jus soli.  Any person born in Venezuela acquires Venezuelan citizenship at birth, irrespective of nationality or status of parents.  Nationality law is regulated by Section 1 of Chapter 2 of the Constitution of Venezuela and by the Nationality and Citizenship Act of 2004 . Nationality law (or citizenship law) is the law in each country and in each jurisdiction within each country which defines the rights and obligations of citizenship within the jurisdiction and the manner in which citizenship is acquired as well as how citizenship may be lost.  A person who is not a citizen of the country is generally regarded as a foreigner, also referred to as an alien.  A person who has no recognised nationality or citizenship is regarded as stateless. Brazilian nationality law is based on both the principles of "jus soli" and of "jus sanguinis".  As a general rule, any person born in Brazil acquires Brazilian nationality at birth, irrespective of status of parents.  Nationality law is regulated by Article 12 of the Brazilian Federal Constitution. Multiple citizenship, also called dual citizenship or multiple nationality or dual nationality, is a person's citizenship status, in which a person is concurrently regarded as a citizen of more than one state under the laws of those states.  There is no international convention which determines the nationality or citizen status of a person, which is defined exclusively by national laws, which vary and can be inconsistent with each other.  Multiple citizenship arises because different countries use different, and not necessarily mutually exclusive, criteria for citizenship.  Colloquial speech refers to people "holding" multiple citizenship but technically each nation makes a claim that this person be considered its national. Nationality is a legal relationship between an individual person and a state.  Nationality affords the state jurisdiction over the person and affords the person the protection of the state.  What these rights and duties are vary from state to state. Israeli nationality law defines the criteria under which a person can be granted citizenship of Israel.  It also deals with the Right of Return for Jewish diaspora.  In general, Israel's nationality follows jus sanguinis as the primary mechanism through which a person may obtain citizenship, rather than jus soli.  A citizen of the modern state of Israel is called an Israeli.
Answer: Dutch