The correct matching of the topics with their descriptions is as follows:

Functional behaviour: The externally observable behaviour with user actions as input operating under certain configurations (A to C).

Quality characteristics: How the system performs the specific behaviour (B to A).

Scenarios: A sequence of actions between an external actor and the system, to accomplish a specific goal or business task (C to B).

Business rules: Activities that can only be performed in the system under certain conditions defined by outside procedures and constraints (D to E).

External interfaces: Description of the connections between the system to be developed and the outside world (E to D)​​.