Final answer:
The correct answer is D. Portability & Reusability. Operational requirements are the essential features and functionalities that a software system needs to fulfill. Memory usage, portability, and reusability are all important operational requirements.
Step-by-step explanation:
The correct answer is D. Portability & Reusability.
Operational requirements are the essential features and functionalities that a software system needs to fulfill.
They are critical for ensuring that the software meets the needs and expectations of the users.
Memory usage is an important operational requirement because it determines how much memory the software uses while running.
Portability is also an operational requirement that refers to the ability of the software to run on different platforms or environments.
Reusability is another operational requirement that involves designing software components that can be used multiple times in different parts of the system or in other systems.
However, Portability & Reusability does not belong to the qualities of operational requirements as they are separate requirements.