单项选择题

下列程序段的执行结果为
a=1
b=0
Select Case a
 Case 1
  Select Case b
   Case 0
    Print"**0**"
   Case 1
    Print"**1**"
  End Select
Case 2
    Print"**2**"
End Select

A.* * 0 * *
B.* * 1 * *
C.* * 2 * *
D.0