EXO-K is a South Korean boy band formed by S.M. Entertainment in April 2012, a sub-unit from the main group EXO, divided into two subgroups, EXO-K and EXO-M, promoting in South Korea and China separately. EXO-K composed of six members: Suho, Baekhyun, Chanyeol, D.O., Kai and Sehun. Their prologue (promotional) single "What Is Love" was released on January 30, 2012. Their second single "HISTORY" was released on March 8, 2012. On April 8, 2012, the group released their third single "MAMA"