Наследование, где у меня ошибка ?

[LM23]

Public MustInherit Class person
    Protected c_sFirstName As String
    Protected c_sLastName As String
    MustOverride ReadOnly Property ClassName() As String
Get
ClassName = "Person"
End Get
End Property
    NotOverridable ReadOnly Property BaseClassName() As String
        Get
            BaseClassName = "Person"
End Get .
    End Property
Overidable Public Property FirstName() as String
Get
FirstName = c_sFirstName
End Get
Set(ByVal Value as string)
c_sFirstName = Value
End Set
End Property
    Public Overridable Property LastName() As String
        Get
            LastName = c_sLastName
        End Get
        Set(ByVal Value As String)
            c_sLastName = Value
        End Set
    End Property
    Overridable Sub Speak()
Console.WriteLine("I am " & c_sFirstName & " " S c_sLastName)
        Console.WriteLine(" and I am a Person.")
    End Sub
End Class

2 класс

Public Class NewPerson
Inherits Person
MustOverride Overrides Public Readonly Property ClassName()as String
Get
ClassName = "NewPerson"
End Get
End Property
Overrides Sub Speak()
Console.WriteLine("My name is " S c_sFirstName S " " &
c_sLastName)
Console.WriteLine(" and I am a new person.")
End Sub
End Public