A large, mission-critical software project carries significant technical and financial risk, and the organization wants to conduct explicit risk analysis and build prototypes at each iteration before formally deciding whether to proceed to the next phase. Which SDLC model is most suitable for this scenario?

The Spiral Model is specifically designed around repeated cycles ("spirals") that each include explicit risk analysis and prototyping steps before the project commits to proceeding further, making it particularly well-suited to large, complex, high-risk projects where technical or financial uncertainty needs to be systematically identified and mitigated at every stage. Waterfall and V-Model both assume requirements and risks are well understood upfront with no iterative risk reassessment; Agile/Scrum focuses more on iterative delivery driven by changing customer requirements rather than formal, structured risk analysis; RAD emphasizes rapid prototyping for fast delivery, but without the Spiral Model's explicit, formalized risk-driven decision gates at each iteration.