The first sitting marks the beginning.
The term begins when the elected Landtag first meets and ends when the next Landtag meets. Election day and the first sitting are therefore not the same legal point in time. A newly elected Landtag must meet no later than the thirtieth day after the election.
Article 9 places the next regular election between 56 and 59 months after the term begins. This is consistent with the answer five years: election day precedes the next parliament’s first sitting. The question asks for the normal parliamentary term, rather than an exact calendar calculation.
The other three answers
The remaining numbers do not describe the normal term.
3
Three years is not the constitutional normal term. An exceptional early election does not change the general rule.
4
Four years is the wrong allocation here. Niedersachsen’s Landtag follows Article 9’s five-year rule.
6
Six years exceeds the normal term. Terms for other offices must not be transferred to parliament.
An earlier election remains possible.
Article 10 allows the Landtag to dissolve itself. At least one third of its members must propose it; approval requires two thirds of those present and at least a majority of all members. A dissolution must be followed by an election within two months.
Five years is not a personal guarantee of office for a Minister President, minister or individual member. Changes in government and individual seats must be distinguished from the parliamentary term.
Article 9 · Parliamentary term · Constitution of Niedersachsen ↗Niedersachsen: Landtag → five years.
Remember the normal term while keeping early dissolution in mind.
Three words for this question
- die Wahlperiodeelectoral term
- A parliament’s term between its constitutionally defined start and end.
- der Zusammentrittfirst sitting
- The first meeting of the newly elected parliament.
- die Auflösungdissolution
- Ending an electoral term early under constitutional rules.