You are employed as the system administrator at Certkiller.com. You make use of MicrosoftASP.NET 3.5 in order to create a Web application. You are in the process of creating a customserver control named Test Circle. Test Circle exists in the Certkiller.WebControls namespace.  TestCircle contains a single read-write property named Radius of type Double. You decide to implement the control as an Asynchronous JavaScript as well as an XML (AJAX) extender controlthat will permit the Radius property to be set in client script. You then implement the following codein an associated JavaScript file (The line numbers are included for reference purposes):  01 Type.registerNamespace("Certkiller.WebControls");  02 Certkiller.WebControls.TestCircle = function(elem)  03 {  04 Certkiller.WebControls.TestCircle.initializeBase(this, elem);  05 this._radius = 0; 06 }  07 Certkiller.WebControls.TestCircle.prototype =  08 {  09 initialize : function（　）  10 {  11 Certkiller.WebControls.callBaseMethod(this, 'initialize');  12 },  13 dispose : function（　）  14 {  15 Certkiller.WebControls.callBaseMethod(this, 'dispose');  16 }, 17  18 }  19 Certkiller.WebControls.TestCircle.registerClass('Certkiller.WebControls.TestCircle',  20 Sys.UI.Control);  You need to identify the Radius property in the JavaScript file. You therefore need to determinethe code segment that should be inserted at line 17.  What should you do?（）

• A、A
• B、B
• C、C
• D、D