Which attribute should you use?

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?

A.
Bindable

B.
Serializable