Look at the error:
Access to the path 'C:\MySqlBackup2016-11-4-8-23-4-270.sql' is denied
It's pretty clear! The folder you are asking MySql to output to does not have write permissions for the user that MySql uses to dump it's data: change the permissions on the folder so that all users can create, delete, read, and write files in the folder.
But please, don't put your path in a hardcoded string: use a configuration file or an application parameter to pass it instead.
And don't store your backups directly in the root folder: set up a folder off the root and create subfolders under that - it's not a good idea to clutter the root, or routinely change anything in it unless it's absolutely necessary.