Source and exercise are different.
Parliament passes laws, government acts and courts administer justice. The fact that these bodies exercise power does not mean it originally belongs to them. The democratic starting point is the people.
“Sovereignty” sounds abstract. For this task, ask a concrete question: from whom must state authority derive its democratic legitimacy? The correct answer names the people, not an individual institution.

The other three answers
The wrong answers confuse a state body or historical ruler with the democratic source.
Bundestag.
The Bundestag exercises important powers, but it is not the original source from which all state authority derives.
Prussian King.
A Prussian king represents historical monarchical rule. The Basic Law gives today’s state authority a democratic basis.
Federal Constitutional Court.
The Federal Constitutional Court protects the constitutional order through its judgments. It does not replace the people as the source of state authority.
Popular sovereignty does not let each individual command everything.
State decisions follow defined procedures and are made by competent bodies. A personal opinion alone does not become a binding state decision.
Democratically legitimate power remains bound by the constitution and fundamental rights. A majority cannot simply discard every legal limit.
Article 20(2) · Basic Law ↗Popular sovereignty asks: where does state authority come from? The people.
Think of the source of power, not just the body currently exercising it.
Three words for this question
- die Volkssouveränitätpopular sovereignty
- The principle that state authority derives from the people.
- die Staatsgewaltstate authority
- The legally organised power of the state.
- ausgehen vonto derive from
- To have its source or starting point in something.
