Dumb Question Oda already answered, this is confirmed from Oda.
Gold Medallists or PK lvl: Roger, WB, Xebec, Garp in that order.
Silver Medalist or Yonko lvl: Shanks, Mihawk, Dragon, Kaido, Rayleigh, BigMom, Shiki, Sengoku etc...
Bronze Medallist Admiral lvl: Admirals, Scopper Gaban, Oden...