My hobby is computer or using computer

[love-you-mom]

I like sitting on computer and using it in general
so for this question;

What is your hobby?

1-I like using computer.
2-I like sitting on computer.
3-I like computer.

Which answer looks better?

 

[probus]

None of them is natural.

A) "I like using the computer" is natural and clear in meaning.

B) "I like sitting at the computer" is closest to the choices you offered, but less clear than A).

 

[Rover_KE]

Note that if you sit on your computer you might squash it.

 

[emsr2d2]

The physical act of sitting on your computer is, as Rover said, a very bad idea. However, you will hear people say "You've been on that computer all day! Come on, let's go out for a walk". In the context of computer use, we do use "to be on the computer" to mean "to be using the computer".