Your question is Design and Build a Complex System. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Tell me about a complex system you built.
Choose a system you personally designed or implemented and explain it as an end-to-end ML system. Cover the product goal, requirements, scale, architecture, data and training pipelines, model and serving choices, evaluation, monitoring, and the most important tradeoffs or failure modes. Be specific about your individual contributions, how the system evolved, and what you would change today.