Task: Question Generation
Input (English): Passage: 4 is the fourth solo studio album by American singer Beyoncé. It was released on June 24, 2011 by Parkwood Entertainment and Columbia Records. Following a career hiatus that reignited her creativity, Beyoncé was inspired to create a record with a basis in traditional rhythm and blues that stood apart from contemporary popular music. Her collaborations with songwriters and record producers The-Dream, Tricky Stewart and Shea Taylor produced a mellower tone, developing diverse vocal styles and influences from funk, hip hop, and soul music.
Severing professional ties with father and manager Mathew Knowles, Beyoncé eschewed the music of her previous releases in favor of an intimate, personal album. 4's lyrics emphasize monogamy, female empowerment and self-reflection, a result of Beyoncé considering a maturer message to contend artistic credibility. In May 2011, Beyoncé submitted seventy-two songs to Columbia Records for consideration, twelve of which appeared on the standard edition.
4 was promoted in mid-2011 by television performances and festival appearances, such as Beyoncé's headlining Glastonbury Festival set. The album received generally positive reviews by music critics; several publications included it on their year-end lists. It was her fourth consecutive album to debut at number one on the US Billboard 200, and it also reached number one in Brazil, France, Ireland, South Korea, Spain, Switzerland and the United Kingdom. 4 spawned the international singles "Run the World (Girls)", "Best Thing I Never Had", "Party", "Love on Top" and "Countdown". "Love on Top" won the Grammy Award for Best Traditional R&B Performance at the 55th annual ceremony. As of December 2015, 4 has sold 1.5 million copies in the United States.
Output (English): What is the last name of the person whose fourth album sold 1.5 million copies in the United States?