阅读程序： Sub subP(b() As Integer) For I =1 To 4 b(I)=2*I Next I End Sub Private Sub Command1_Click() Dim a(1 To 4)As Integer a (1)=5 a (2)=6 a (3)=7 a (4)=8 subP a () For I =1 To 4 Print a(I) ; Next I End Sub 运行上面的程序，单击命令按钮，输出结果为（ ）。
A.2 4 6 8
B.5 6 7 8
C.10 6 7 8
D.出错
正确答案是A