All of the above except penalizing
can be forms of bullying. What's the determining factor for me is intent. If the intent is to upset someone in some way, that's bullying. If someone asks you not to do something and there isn't any reason you can't comply (for example, continuing to stim in some way after someone has asked you to stop is acceptable if you explain why you can't, but continuing to correct someone's grammar while they're speaking after the person has asked you not to, that isn't), that can also be bullying because once someone has asked you to stop, you know they don't like it, so not making any effort not to do it to/around them(and of course doing it more on purpose, as some people do

) could be seen as deliberately bothering them, which would count as bullying. But then things like teasing among friends, where the person doing the teasing is not intending to hurt the recipient, is not bullying (though if the recipient tells the teaser that they don't like it and they continue to do it, that is). If someone accidentally annoys or hurts someone else, that is not bullying, that is an honest mistake. It only becomes bullying if the person knows what effect their action had and does not apologize or try not to make the same mistake again.
I agree with this & won't vote since this is all relative based on intent & the poll doesn't factor that in.
However as a kid I was bullied alot & the teachers usually said how the bullies were just joking & I took things personally that weren't meant to be. & I was accused of bullying when I retaliated or accidentally did or said something the wrong way or when I was joking around. I don't know how the f#ck bullying is defined except that bullies sometimes don't get called on their sh!t but the people retaliating against them get the bully label. The definition is all relative depending on the person's social status.