Legendary producer Rick Rubin produced what "Artpop" track?

Explanation

"Artpop" (stylized as ARTPOP) is the third studio album by American recording artist Lady Gaga, released on November 6, 2013. It debuted at number one on the U.S. Billboard 200 with first-week sales of 258,000 copies, becoming Gaga's second consecutive number-one record in the United States. The album includes the singles "Applause" and "Do What U Want".