Decompose: design a data platform for an enterprise with 500 disparate data sources.

The strongest answers invert the prompt inside the first two minutes: not 'how do I ingest 500 sources' but 'which decisions does this enterprise want to make, and what is the smallest set of sources that supports them.' In the reported versions of this round the interviewer keeps adding sources to see whether your design degrades gracefully or whether you were quietly assuming you would model all of them. A candidate who has already said 'we will never model the long tail, it stays schema-on-read' has pre-answered the escalation.