Your question is Scale an Application. 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 scale the application?
Asked in the Operational and Engineering Excellence stage. Treat this as an end-to-end ML system design discussion. Begin by identifying the missing product, traffic, data, latency, availability, and cost requirements, then explain how those requirements determine the architecture. Cover online and batch workloads, model serving, data growth, deployment strategy, monitoring, and failure recovery. Do not assume a particular application domain. State your assumptions clearly and explain how you would validate them.