original_query: Who was the most prominent member of the Slavs, advocating for a federation to counter Serbian hegemony in a common South Slavic state?
query: Who was the most prominent member of the Yugoslav Committee advocating for a federation to counter Serbian hegemony in a common South Slavic state?
answer: Frano Supilo was the most prominent member of the Yugoslav Committee, advocating for a federation to counter Serbian hegemony in a common South Slavic state.