有如下 VB 程序段：

Dim s As String, t As String, res As String Dim i As Integer, k As Integer

s = "jpqzaabdcfb"

i = 1: k = 1: res = "" t = Mid(s, 1, 1)

Do While i < Len(s)

    If Mid(s, i + 1, 1) >= Mid(s, i, 1) Then

        k = k + 1

    Else

        res = res + CStr(k) + t

        k = 1

        t = Mid(s, i + 1, 1)

    End If

    i = i + 1

Loop

Label1.Caption = res

执行该段程序段后，Label1中输出的值为 （    ）

A、4j1a3a2c1b

B、4j4a2c1b

C、4j4a2c

D、4j1a3a2c