Why do i get an Error?

```cs string inputChoice = Console.ReadLine()?.ToLower(); if (string.IsNullOrWhiteSpace(inputChoice)) { Console.WriteLine("Invalid"); } if (inputChoice == null) { Console.WriteLine("Invalid"); } ``` Error is CS8600 "the null literal or a possible null value will be converted into a non nullable type" Sorry if its completly stupid, its my first C# Code. Please also feedback my code https://discord.com/channels/693908458986143824/1185995438944432189 🙂