Riddle: Thomas-Alekhine 1925

The famous classic Thomas-Alekhine is a strategical masterpiece. It has served as a lesson on how to play against weak white pawns on c3 and d4. Ever since Nimzovitsch has dealt with it in his famous work “My System” it has been popular with trainers and students alike. But did White really use all defensive options? This has not been debated enough in the past. Can you do this important job?