有如下VB程序段：

c = 0 :i = 1

Do While i <=6

  k = i

  For j = i + 1 To 7

    If a(j)<= a(k) Then k = j

  Next j

  If a(i) <> a(k) Then

   t = a(i): a(i) = a(k): a(k) = t

   c = c + 1

  End If

  i = i + 1

Loop

数组元素a(1)到a(7)的值依次为“9,9,8,16,45,9,78”。该程序段执行后，变量c的值是（  ）

A、0

B、3

C、4

D、6