有如下VB程序段：

Dim a(1 To 8) As Integer Dim i, j, m, k As Integer i = 1: j = 8

a(1) = 87: a(2) = 66: a(3) = 59: a(4) = 40: a(5) = 39: a(6) = 30: a(7) = 22: a(8) = 13

k = Val(Text1.Text)

Do While i <= j

  m = (i + j + 1) \ 2

  If a(m) < k Then

    j = m - 1

  Else

    i = m + 1

Loop

Text2.Text = Str(i)

程序执行完后，i的值是4，则k的值不可能是（   ）

A、40

B、41

C、48

D、59