有如下VB程序段

Dim c As Integer,a(0 To 5) As Integer

For i = 1 To 5

  a(i) = i

Next i

c = 0

For i = 1 To 5

  x = Int(Rnd * 5 + 1)

  If a(x Mod 5) = i + 2 Then c = c + 1

  If c = x Then Exit For

  i = i - 1

Next i

运行该程序后，变量c的值不可能是（  ）

A、1

B、2

C、3

D、4