Elazar Menachem Man Shach (Hebrew: אלעזר מנחם מן שך‎ ) Elazar Shach (January 1, 1899 O.S. – November 2, 2001) was a leading Lithuanian-Jewish Haredi rabbi in Bnei Brak, Israel. He also served as one of three co-deans of the Ponevezh Yeshiva in Bnei Brak, along with Rabbis Shmuel Rozovsky and Dovid Povarsky.
Rabbis Shmuel Rozovsky and Dovid Povarsky were co-deans of the Ponevezh Yeshiva in Bnei Brak before Elazar Shach.
It's neither definitely correct nor definitely incorrect because it's not mentioned in the text when any of them became co-deans and how long they served as co-deans. I think the system got it wrong because many of the words in the question are in the text, so it figured the answer must be correct without understanding what the question was asking.