Your question is System Design Exercise. 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).
Design a system for a real-world use case, and walk me through your approach and tradeoffs.
Choose a concrete ML use case, clarify the product and operational requirements, and explain how you would take it from data collection through production serving. Cover the system architecture, scale assumptions, model choices, online and batch components, evaluation plan, monitoring, and major failure modes. Be explicit about tradeoffs involving latency, cost, accuracy, freshness, reliability, privacy, and maintainability.