单项选择题

有下面程序代码：
Private Sub Commandl_Click( )
Dim a
a = Array(1, 2, 3, 4, 5)
Call proc(A)
For k = 0 To 4
Print a(k);
Next k
End Sub
Private Sub proc(ByVal x)
For k = LBound(x)To UBound(x)
x(k) = x(k) * 2
Next k
End Sub
运行Command1_Click过程产生的输出是______。