Belonging to the same branch does not mean identical membership.
The Bundestag consists of elected MPs. The Bundesrat consists of members of state governments. The two bodies therefore have different democratic and institutional foundations, but both participate in federal legislation.
The exam assigns this participation to a branch of state power. Their shared feature is lawmaking, rather than day-to-day administration or deciding a court case.
The other three answers
The other terms do not fit the lawmaking function described here.
Executive.
The executive includes government and administration. State-government members in the Bundesrat perform a distinct participatory role at federal level.
Directive.
“Directive” is not one of the three branches of state power. It is not an alternative classification to the legislature here.
Judiciary.
The judiciary is the adjudicating branch of the courts. The Bundestag and Bundesrat are not courts.
Bundesrat participation differs between types of laws.
Consent bills require Bundesrat consent. Objection bills involve different possibilities for participation and objection. The short exam answer does not remove these procedural distinctions.
Under Article 50, the Bundesrat also participates in federal administration and European Union matters. The classification in this question highlights its legislative function.
Articles 50 and 77 · Basic Law ↗Bundestag + Bundesrat + federal laws → legislature.
Classify by the function in the procedure, not just the other offices held by individual members.
Three words for this question
- die Gesetzgebunglegislation
- The process through which laws are made.
- das Zustimmungsgesetzconsent bill
- A law requiring Bundesrat consent.
- die Ländervertretungrepresentation of the states
- Participation by state governments through the Bundesrat.