In a Microsoft .NET Framework 4 application that uses the ADO.NET Entity Data Model (EDM), you have defined a Customer entity. You want to add a new Customer row to the data store without having to set all of the Customer properties explicitly before the object is created. What is the correct way to create this new Customer instance so that default values are handled correctly by the Entity Framework?

Introduction / Context:
In applications that use the ADO.NET Entity Data Model (EDM) and Entity Framework, developers typically work with strongly typed entity classes such as Customer instead of writing raw SQL insert statements. The framework provides helper methods that know how to create properly initialized instances that match the model metadata. This question tests whether you understand how to create a new entity object (Customer) without explicitly setting all properties yourself, while still letting Entity Framework manage defaults and mapping to the underlying data store.

Given Data / Assumptions:

• The application is built with Microsoft Visual Studio 2010 and .NET Framework 4.
• An ADO.NET Entity Data Model (EDM) defines an entity named Customer.
• You want to add a new Customer to the data store.
• You do not want to manually set every property of the Customer before adding it.
• Entity Framework should be able to handle default values and required metadata.

Concept / Approach:
In Entity Framework 4 with the EDM, ObjectContext (and its ObjectSet properties) knows how to create instances of entities that are tracked by the context. The CreateObject method on an ObjectSet (for example, context.Customers.CreateObject()) or the generic CreateObject<T> on ObjectContext creates a new entity instance that is connected to metadata, default values and the change tracker. Simply using the entity class constructor or an arbitrary Create method on the entity type will not automatically wire it to the ObjectContext. Therefore, the correct approach is to use CreateObject so that the new entity instance is fully recognized by the framework when you later call AddObject and SaveChanges.

Step-by-Step Solution:
1. Start with an ObjectContext (for example, MyEntities context = new MyEntities();). 2. Use the ObjectSet for Customer (for example, context.Customers) to create a new Customer entity. 3. Call the CreateObject method (for example, Customer c = context.Customers.CreateObject();). 4. Optionally fill only those Customer properties that you need (such as Name or Email) and leave other properties at their default values. 5. Add the Customer to the context by calling AddObject on the ObjectSet and commit the change with SaveChanges so that the row is inserted into the database.

Verification / Alternative check:
If CreateObject is used correctly, the new Customer instance is tracked by the context and is associated with its metadata. When SaveChanges runs, Entity Framework generates an INSERT statement that includes the correct columns and lets the database apply default values for any omitted fields. If you instead use a simple constructor with new Customer(), you must manually ensure that the entity is attached and that required properties are all set, or you might receive validation exceptions or mapping issues. Using CreateObject therefore offers a safe and recommended method to create valid entities with minimal manual work.

Why Other Options Are Wrong:
Option A is incorrect because there is no standard Create method on the Customer entity that automatically wires the instance to the ObjectContext; it is not the Entity Framework pattern. Option C is incorrect because overriding a Create method on Customer still does not automatically integrate with the EDM metadata and tracking, and it adds unnecessary complexity. Option D is incorrect because overriding SaveChanges to fill missing properties mixes responsibilities, makes the code harder to maintain, and still does not solve the need for a properly initialized entity instance at creation time.

Common Pitfalls:
A common mistake is to think that simply calling new Customer() is enough for Entity Framework to track the entity with complete metadata, or to try to manage all defaults and constraints manually. Another pitfall is attempting to use SaveChanges as a generic hook to fix missing properties, which can hide bugs and lead to inconsistent data. Developers may also confuse CreateObject with methods that belong to custom business logic, but CreateObject is specifically designed to work with the EDM and ObjectContext. Understanding the difference between constructing a plain CLR object and creating a tracked entity object is important in real-world applications.

Final Answer:
The correct approach is to call the CreateObject method of the Customer object or ObjectSet so that a properly initialized Customer entity is created and can be saved without explicitly setting all properties.