Question: Chou Tzu-yu is part of the girl group who debuted on October 20, 2015 with what EP?
Sentence (from "Chou Tzu-yu"): Chou Tzu-yu (born June 14, 1999), known as Tzuyu, is a Taiwanese singer based in South Korea and a member of the K-pop girl group Twice, under JYP Entertainment.
Relevant evidence: Yes