单选题 The traditional model for systems development was that an IT department used ______ which is a process-centered technique, and consulted users only when their input or approval was needed. Compared with traditional methods, many companies find that JAD allows ______ to participate effectively in the requirements modeling process. When properly used, JAD can result in a more accurate statement of system requirements, a beret understanding of common goals, and a stronger commitment to the success of the new system. RAD is a ______ technique that speeds up information systems development and produces a functioning information system. While the end product of JAD is a(an) ______，the end product of RAD is the new information system. The RAD model consists of four phases. During the ______, users interact with systems analysts and develop models and prototypes that represent all system processes, outputs, and inputs.