Public sector organisation can be of four types depending on the types of ownership, responsibilities, objective and the management style.
Refrence:-
https://www.google.co.in/search?q=types+of+public+enterprises&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiT0--x5pfYAhXJA8AKHbU-DFkQ_AUICygC&biw=1366&bih=662#imgrc=Kn