How would you answer an interview scenario involving dependency injection in Angular?

For an interview scenario involving dependency injection, I would first clarify the business goal, scale, constraints, and the failure or quality attribute the interviewer wants to explore. Angular dependency injection creates and provides service instances based on provider configuration and injector hierarchy. In this scenario, if two parts of a feature must share the same stateful service instance but other features should not, provide the service at the feature boundary rather than on every child component. For production, use providedIn root for application-wide stateless services, component providers for intentionally scoped instances, and injection tokens for configurable or interface-like dependencies. 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.