Question: What album was the song Gentleman on?
Related documents: [0]  [DOC] "Gangnam Style" (Korean: 강남스타일 , ] ) is the 18th K-pop single by the South Korean musician Psy. The song was released on July 15, 2012, as the lead single of his sixth studio album "Psy 6 (Six Rules), Part 1", and debuted at number one on South Korea's Gaon Chart. On December 21, 2012, "Gangnam Style" became the first YouTube video to reach one billion and two billion views. The song's music video has been viewed over 2.9 billion times on YouTube, and was the most viewed video on YouTube from November 24, 2012, when it surpassed the music video for "Baby" by Justin Bieber featuring Ludacris, to July 10, 2017, when it was surpassed by the music video for "See You Again" by Wiz Khalifa featuring Charlie Puth. [END] 
[1]  [DOC] "Gentleman" is a K-pop song by South Korean musician Psy released on April 12, 2013 (KST), serving as his 19th single. The song serves as the follow-up to his international hit single "Gangnam Style", which at the time of "Gentleman"'s release had been viewed on YouTube over 1 billion times. The first public performance of the song, with its associated dance, was unveiled at 6:30 pm on April 13 at Seoul World Cup Stadium in Seoul. A poster and Twitter message was released containing the main line of the song "I'm a mother f••••• gentleman"; The obscured word was later revealed to be "father". [END] 
Answer: 
Psy 6 (Six Rules), Part 1
Psy 6 (Six Rules), Part 1