Your question is Design the System for the Problem. 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).
How would you design the system for this problem?
Clarify the product objective, users, data sources, and success criteria before proposing an architecture. Cover the end-to-end ML lifecycle, including data collection, training, retrieval or candidate generation where applicable, ranking, online serving, evaluation, monitoring, and failure recovery.