有如下 VB 程序段：

Dim a(1 To 6) As Integer

Dim d(1 To 6) As Integer

a(1) = 10: a(2) = 21: a(3) = 28: a(4) = 11: a(5) = 12: a(6) = 30

Const n = 6

For i = n To 1 Step -1

    d(i) = 0

    For j = n To i +1 Step -1

        If a(j) > a(i) Then d(i) = d(j) + 1

    Next j

    If d(i) > Max Then Max = d(i)

Next i

Text1.Text = Str(Max)

执行该程序段，文本框Text1中显示的是（   ）

A、1

B、2

C、3

D、4