下面的程序代码是通过函数求出二个整数型变量a、b中的较大值，其中所定义的函数名是（   ）
Function max(a, b As Integer) As Integer
If a > b Then max = a  Else  max = b
End Function
Private Sub Command1_Click()
Dim a As Integer, b As Integer, s as integer
a =" Val(Text1.Text):" b = Val(Text2.Text)
s =" max(a," b)
Text3.Text = s
End Sub

A．Command1_Click

B．function

C．max

D．max(a, b As Integer)