class Program

{

    static void Main(string[] args)

    {

        BaseClass baseClass = new BaseClass();

        System.Console.WriteLine(baseClass.GetFavoriteComposer()); // Outputs: Composer

        DerivedClass derivedClass = new DerivedClass();

        System.Console.WriteLine(derivedClass.GetFavoriteComposer()); // Outputs: Mozart    

    }

}

​

public class Composer { }

​

public class Mozart : Composer { }

​

public class BaseClass

{

    public virtual Composer GetFavoriteComposer()

    {

        return new Composer(); // Returns a Composer object

    }

}

​

public class DerivedClass : BaseClass

{

    // This is not allowed before C# 9.0

    public override Mozart GetFavoriteComposer() // Returns a Mozart object

    {

        return new Mozart();

    }

}

​