All 7 of them!
It’s useful to know, but not the whole story.
For example if you asked most people what the main constituent of whole fat milk was, most people would say fat. It’s actually sugar (lactose).
Also, it depends on how available these sugars are. Fruits and veg have sugars (think why carrot cake works), but think how the amount of fibre and other things change the speed sugar can be processsed, and sometimes don’t actually allow these to be bioavailable. This is why the GI for things with similar sugar contents can vary so much.
This is why added sugars are an issue. They are normally very easily digestible, and so have a big effect on spiking insulin and everything that leads to. Also foods being liquidised needs to be considered. Think eating and orange (good), vs orange juice (similar to sugaring pop).