Apprentices and trainees shall be distinguished from employees. The former is a student learning the relevant art or profession and apprenticeship is a part of their education. Trainees, on the other hand, are qualified with the relevant theoretical information and seek to improve their practical skills. Neither group qualifies as an employee and are not considered within employee count of the establishment. They are not subject to the Labour Act, but benefit from the provisions of the Act on Occupational Health and Safety, as well as the social insurance for occupational hazards and diseases. Therefore, the correct option is C.