The type or namespace name 'nullable' could not be found (are you missing a using directive or an assembly reference?) [closed]

Question

In a C# file when I try to run the file, Am getting the above error. Probably, I must have deleted the namespace by mistake and am not able to find it now. Kindly let me know what is the namespace to be used for nullable type.

Answer 1

Point your cursor to the Nullable then press Ctrl+..

BTW its using System;