有如下程序段
Dim a(1 To 6) As String i = 6
Text1.Text = ""
Do While i > 1
k = i
For j = 1 To i - 1
If a(k) < a(j) Then k = j
Next j
tmp = a(k): a(k) = a(i): a(i) = tmp
Text1.Text = a(i)
i = i - 1
Loop
其中数据元素 a(1)到a(6)的值依次为“12”、“34”、“8”、“9”、“77”、“23”,执行该程序段后,文本框Text1中显示的内容为( )