I.O.I KOREAN I.O.I – Knock Knock Knock (똑 똑 똑) 똑 똑 똑 ttok ttok ttok “Knock Knock Knock” [EP] Chrysalis 2016.05.04 Nayoung, Chungha, Sejeong, Chaeyeon, Jieqiong, Sohye, Yeonjung, Yoojung,…