You are developing an order processing application that uses the Entity Framework against a SQL Server database. Lazy loading has been disabled. The application displays orders and their associated order details. Order details are filtered based on the category of the product in each order.

You need to return orders with their filtered list of order details included in a single round trip to the database.
Which code segment should you use?
A:

B:

C:

D:

Correct Answer: C
Explanation/Reference:
Explanation:
Eager loading is the process whereby a query for one type of entity also loads related entities as part of the query. Eager loading is achieved by use of the Include method. For example, the queries below will load blogs and all the posts related to each blog.
using (var context = new BloggingContext())
{
// Load all blogs and related posts
var blogs1 = context.Blogs
.Include(b => b.Posts)
.ToList();
It is also possible to eagerly load multiple levels of related entities.
References:
https://msdn.microsoft.com/en-us/library/jj574232(v=vs.113).aspx