What is the name of a South Korean singer that was one of six members in a girls group named "Apink"? 
Apink discography:  The group consists of six members: Chorong, Bomi, Eunji, Naeun, Namjoo, and Hayoung. Son Na-eun: Son Na-eun (born February 10, 1994) is a South Korean singer.
i don't know