All of them are correct. Electricity is generated by moving turbines with the help of WATER, wind, STEAM. ( remember steam engine rails. The steam used to drive the engine and now we are in situation to generate electricity from it also)
From sun also, solar cells are able to generate electricity by using photo voltaic cells.
With Nuclear energy, you are talking about controlled reaction or uncontrolled? Both are pretty dangerous as they gotta take place on large scale and any error can vanish entire patches of states.
From Natural gas/biogas/diesel/petrol also, we are able to drive engines (Compressed natural gas) so that can ALSO be used to generate electricity.
I was taught this stuff when i was 14 in school. Is the mod trying to complete his school homework or what? :P
P.S: The power company does all these stuff and divides the power circuits among the residents of the city.