--___ do you want?  --I want a book on history.

A．Which books

B．What book

C．How many books

D．Whose book

某个窗体己编写以下事件过程。打开窗体运行后，单击窗体，消息框的输出结果为 【11】 。
Private Sub Form_Click()
Dim k as Integer， n as Integer，m as Integer
n=10 ：m=1 : k=1
Do While k＜=n
m=m*2
k=k+1
Loop
MsgBox m
End Sub