设有如下程序：
Private Sub Form_Load()
Show
Dim b()As Variant
Dim n As Integer
b=Array(21, 64, 92, 15, 72, 38, 45, 72)
Call search(b，45，n)
Print n
End Sub
Private Sub search(a()As Variant, ByVal key As Variant, index%)
Dim i %
For i=LBound(a)To UBound(a)
If key=a(i) Then
index=i
Exit Sub
End If
Next i
index=-1
End Sub
程序运行后，输出结果是______。

A) 2
B) 6
C) 10
D) 12

板式无砟轨道砼底座板工艺原理？