You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5.
You create a Web form in the application by using the following code fragment. (Line numbers are included for reference only.)
You plan to create a client-side script code by using ASP.NET AJAX.
You need to ensure that while a request is being processed, any subsequent Click events on the btnSubmit Button control are suppressed.
Which code fragment should you insert at line 10?()
A.A
B.B
C.C
D.D