Admin approval notification based on role choose by user on registration form?
I have created a module for this, which addresses my question. It can be found at Select registration roles. Some more details about it (from its project page):


  The Select Registration Roles module adds a role field on the user registration form. Admin can configure roles to be displayed on the
  registration form as, and can set roles which require admin approval.


Here is a screenprint of it also: