You are implementing an ASP.NET application that will use session state in out-of-proc mode. You add the following code. Public Class Person Public Property FirstName As String Public Property…

You are implementing an ASP.NET application that will use session state in out-of-proc mode. You add the following code. Public Class Person Public Property FirstName As String Public Property LastName As String End Class You need to add an attribute to the Person class to ensure that you can save an instance to session state. Which attribute should you use?