C# Option 1

Program.cs

using System;

namespace option {
    class Program {
        static void Main(string[] args) {
            string message;
            var option = GetOption(true);
            Console.WriteLine(EvaulateOption(option));
            Console.ReadLine();
        }

        static Option GetOption(bool ifSome) {
            return ifSome ? new Some<string>("Hello!") : new None() as Option;
        }

        static string EvaulateOption(Option option) {
            switch (option) {
                case Some<string> s:
                    return s.Value;
                case None n:
                    return "None";
                default:
                    return "Default";
            }
        }
    }

    abstract class Option {
        
    }

    class Some<T> : Option {
        public T Value { get; }

        public Some(T value) {
            Value = value;
        }
    }

    class None : Option {
        
    }
}