You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5. 
You add a TextBox control named TextBox1. 
You write the following code segment for validation. 
protected void CustomValidator1_ServerValidate( 
object source, ServerValidateEventArgs args) { 
DateTime dt = String.IsNullOrEmpty(args.Value) 
DateTime.Now : Convert.ToDateTime(args.Value); 
args.IsValid = (DateTime.Now - dt).Days < 10; 
} 
You need to validate the value of TextBox1. 
Which code fragment should you add to the Web page?（）

A.
B.
C.
D.
E.
F.
G.
H.