You have to write Group 2 exams of the State you are from. You can study any stream in your 12th and Graduation. You have to write APPSC or TSPSC. You should complete your Graduation in any stream. There is no specialisation or particular course that you have to study to become a MRO. You have to write APPSC if you are from Andhra Pradesh and TSPSC if you are from Telangana.