What are the three core hypotheses in Lean Startup methodology and how are they tested?

What are the three core hypotheses in Lean Startup methodology and how are they tested?

• A. Market size, distribution channels, and revenue streams; tested via market research.
• B. Product features, user interface, and branding; tested via usability testing.
• C. Competition analysis, pricing strategy, and channel mix; tested via sales data.
• D. Problem/needs, solution, and business model; tested via experiments, MVPs, and validated learning.

Answer: (D)