Question:You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5. You create a custom
control named OrderForm.
You write the following code segment:
    public delegate void CheckOrderFormEventHandler(EventArgs e);
    private static readonly object CheckOrderFormKey = new object();
    public event CheckOrderFormEventHandler CheckOrderForm
       {
           add { Events.AddHandler(CheckOrderFormKey, value); }
           remove { Events.RemoveHandler(CheckOrderFormKey, value); }
         }
You need to provide a method that enables the OrderForm control to raise the CheckOrderForm event.
Which code segment should you use? 

A protected virtual void OnCheckOrderForm(EventArgs e) {
 CheckOrderFormEventHandler checkOrderForm = (CheckOrderFormEventHandler)Events
 [typeof(CheckOrderFormEventHandler)];
 if (checkOrderForm != null)
 checkOrderForm(e);

B protected virtual void OnCheckOrderForm(EventArgs e) {
 CheckOrderFormEventHandler checkOrderForm = Events[CheckOrderFormKey] as
 CheckOrderFormEventHandler;
 if (checkOrderForm != null)
 checkOrderForm(e);

C CheckOrderFormEventHandler checkOrderForm = new CheckOrderFormEventHandler
(checkOrderFormCallBack);
protected virtual void OnCheckOrderForm(EventArgs e) {
 if (checkOrderForm != null)
 checkOrderForm(e);

D CheckOrderFormEventHandler checkOrderForm = new CheckOrderFormEventHandler
(checkOrderFormCallBack);
protected virtual void OnCheckOrderForm(EventArgs e) {
 if (checkOrderForm != null)
 RaiseBubbleEvent(checkOrderForm, e);

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