How would you answer an interview scenario involving transactions and optimistic concurrency in Entity Framework Core?

For an interview scenario involving transactions and optimistic concurrency, I would first clarify the business goal, scale, constraints, and the failure or quality attribute the interviewer wants to explore. Transactions group database operations atomically, while optimistic concurrency detects conflicting updates without long locks. In this scenario, two users edit the same invoice. Explain how you would detect and resolve the conflict. For production, keep transactions short, use rowversion or other concurrency tokens where appropriate, and handle DbUpdateConcurrencyException explicitly. I would then explain the main alternatives and tradeoffs, identify likely failure modes, and describe how I would validate the solution through testing, observability, security controls, and recovery or rollback planning.