单项选择题

以下程序输出的结果是________。 Dim i% Dim a() As Integer={1, 2, 3, 4, 5, 6, 7} For i =0 To UBound (a) a(i) = a(i) * a(i) Next i MsgBox(a(i))

A、程序出错
B、49
C、0
D、7
E、不确定