Question: Which of the four members of the South Korean girl group Red Velvet, is both a member and leader?
Sentence (from "Red Velvet discography"): The discography of the South Korean girl group Red Velvet consists of one studio album, five extended plays, and twelve singles. Red Velvet was formed by the Korean entertainment company S.M. Entertainment in 2014, and consists of five members.
Relevant evidence: No