The document describes 5 tools for answering the business viability question: 1) traditional business plans, 2) blue ocean strategy, 3) design thinking, 4) discovery-driven planning, and 5) lean startup method. Each tool is described in terms of its objective, stages/roadmap, criteria for progress, and strengths and weaknesses for addressing risks for new projects at both mature companies and startups. The lean startup method emphasizes carrying out low-cost experiments, using real options thinking, and continuously validating learning through a build-measure-learn loop.