Question: Which musical artist is in a duo with the American rapper who released the single "Rock City?"
Sentence (from "Rock City discography"): The discography of Rock City (also known as R. City and Planet VI)—a songwriting and record production duo from Saint Thomas, U.S. Virgin Islands—consists of one studio album, 16 mixtapes, eight singles (including four as a featured artist) and 21 music videos. Rock City is primarily known for their songwriting and production, having written or produced songs such as "Pour It Up" by Rihanna, "Replay" by Iyaz, "Bow Down/I Been On" by Beyoncé and "We Can't Stop" by Miley Cyrus.
Relevant evidence: No