Just like the Campeonato Brasileiro, groups during the reduced series, for example B and C, could be promoted to the very best division annually. In the case of Italy, only the leading 3 teams in Serie B are promoted to Serie A (in Brazil, promotion happens for 4 teams in https://andyqoecp.elbloglibre.com/37711513/the-smart-trick-of-what-is-serie-a-that-nobody-is-discussing