• (A) It describes the basic entities in the design and relation between them.
• (B) Observational techniques used to understand social and organizational requirements.
• (C) It is based on the idea of developing an initial implementation, exposing it uses on requirement and refining it through many versions until an adequate system has been developed.
• (D) Based on an idea of developing an initial implementation, exposing this to uses comment and retiring it until and adequate system has been developed.