Answer 1

https://www.sololearn.com/Course/CSharp/

https://stackify.com/learn-c-sharp-tutorials/
https://www.microsoft.com/net/learn/in-browser-tutorial/1
https://www.microsoft.com/net/learn/what-is-dotnet
https://docs.microsoft.com/en-us/dotnet/csharp/quick-starts/
http://www.learncs.org/
http://csharp.net-tutorials.com/
https://www.tutorialspoint.com/csharp/
http://www.homeandlearn.co.uk/csharp/csharp.html