Incorrect: A WCF data service would be an ideal solution; however, it supports only OData and REST. WCF Data Services do not support .NET-only protocols.

Correct: WCF Web Services provide a great deal of flexibility, and they support using multiple binding types.

Incorrect: SQL Server Express edition does not support the different protocol requirements. In addition, you should avoid exposing database servers to the public Internet because doing so presents a significant security risk.

Incorrect: An Entity Data Model is useful for accessing a database directly from an application. In fact, you might choose to generate an Entity Data Model in the application. However, you then will need to create a WCF web service to allow other clients to access the data across the network.