Override.cs

public class Product(int id, OfferingType type)
{
    public virtual Option<string> GetDownloadUrl()
    {
        return Option.None<string>();
    }

    public virtual Option<string> GetDefaultDownloadFileName()
    {
        return Option.None<string>();
    }
}

public class DownloadProduct(int id, OfferingType type) : Product(id, type)
{
    public override Option<string> GetDefaultDownloadFileName()
    {
        return Option.Some("Some Value");
    }

    public override Option<string> GetDownloadUrl()
    {
        return Option.Some("Some Value");
    }
}

public class Course(int id, OfferingType type) : Product(id, type)
{
    public override Option<string> GetDefaultDownloadFileName()
    {
        return Option.None<string>();
    }

    public override Option<string> GetDownloadUrl()
    {
        return Option.None<string>();
    }
}

public sealed class ProductHandler()
{
    public void DoStuff(Product product)
    {
        product.GetDefaultDownloadFileName().MatchSome(
            filename =>
            {
                // Do something with the filename.
            });
        
        product.GetDownloadUrl().MatchSome(
            url =>
            {
                // Do something with the url
            });
    }
}