Question: What was the name used by the singer whose debut mini-album was Walkin' when she appeared as a contestant on "King of Mask Singer"?
Sentence (from "Suran (singer)"): Shin Su-ran (Hangul: 신수란), also known by her stage names Elena (Hangul: 엘에나) and Baily Shoo (Hangul: 베일리 슈), and better known by the mononym Suran (Hangul: 수란), is a South Korean singer-songwriter and record producer.
Relevant evidence: Yes