Imo 3 could be any/both.
Like on heating if you have any bicarbonate you are converting it into carbonate and then it ppt.
If you have only carbonate, the heating doesn't do anything and you still will get ppt.
So no conclusion.
Not sure about 2 but I think because the agent we add is basic, HCO3- will get converted to CO32- if present.
So we cant really say if it had both or only CO32-