You are designing a Windows Presentation Foundation (WPF) application by using Microsoft .NET Framework 4 and Microsoft Visual Studio 2010. You plan to create a Customer object that contains an…

You are designing a Windows Presentation Foundation (WPF) application by using Microsoft .NET Framework 4 and Microsoft Visual Studio 2010. You plan to create a Customer object that contains an Orders property. The Orders property contains an array of Order objects. When users browse Customer objects, they must be able to optionally view Order objects. You need to design a data access strategy that retrieves data only when necessary. Which strategy should you use?