128A fortiori, there is also no reason to consider that the burden of proof is reversed with regard to the examination of whether an existing aid scheme is compatible with the internal market. As argued by the Commission, the Member State concerned and interested parties are free to challenge the provisional reasoning of the Commission in that respect during the formal investigation procedure. The Member State and, to a lesser extent, interested parties are generally best placed to determine whether a public interest objective was pursued when the measure at issue was adopted, which would enable that measure to be declared wholly or partly compatible.