Se diria yo soy "colombiano"
You woudl say I am "Columbian"
It wouldn't be colombiana because its a guy we are talking about not a girl, and we wouldn't say comobia because that is the country like you wouldn;t say I am united states you would say I am american. adn it wouldn't be vengo de colombia becuase that means I come from colombia and that doesnt match with the question
Hope this helps
