A .NET web app uses the Cosmos DB Core API and must support millions of reads/writes with the account configured for multiple write regions. The app is deployed in East US2 and Central US. What two client-side changes can enable multi-region writes from the application?

To enable multi-region writes from a .NET application using the Cosmos DB Core API, two key client-side configurations are necessary. First, setting the UseMultipleWriteLocations property of the ConnectionPolicy class to true explicitly tells the Cosmos DB client to allow writes to any configured write region. Second, populating the PreferredLocations property in the ConnectionPolicy with a list of preferred Azure regions, ordered by geo-proximity to the application, allows the client to intelligently route requests to the nearest available region, optimizing latency for both reads and writes. Incorrect options: Changing consistency levels (Strong or Session) or adding indexed properties are server-side configurations and do not directly enable multi-region writes from the client. Creating a custom conflict resolution policy is for handling write conflicts, not for enabling multi-region writes themselves.