Table:
text: List of South Korean surnames by prevalence
List
List
Hangul Hanja Revised McCune_Reischauer _2000_n_South_Korea_population_
임 (S) 림 (N) 林, 任 Im (S) Rim (N) Im (S) Rim (N) 735493
한 韓, 漢 Han Han 715556
오 伍, 吳 O O 706908
서 西, 徐 Seo Sŏ 695249
전 全, 田, 錢 Jeon Chŏn 687867
권 權 Gwon Kwŏn 652495
황 黃 Hwang Hwang 644294
송 宋, 松 Song Song 639082
안 安 An An 637786
홍 洪 Hong Hong 518635
양 (S) 량 (N) 梁, 楊, 樑, 襄 Yang (S) Ryang (N) Yang (S) Ryang (N) 486645
고 高 Go Ko 435839
문 門, 文 Mun Mun 426927
손 孫 Son Son 415182
배 裵 Bae Pae 372064
백 白 Baek Paek 351275
허 許 Heo Hŏ 300448

Question: What is the hanja for McCune-Reischauer of Chŏn in the list of South Korean surnames by prevalence?

Question: What is the hangul if the hanja 西, 徐 is among South Korean surnames by prevalence?