Task: Question Answering
Input (English): Passage: Stung by the criticism of Rattle and Hum, the band sought to transform themselves musically. Seeking inspiration from German reunification, they began work on their seventh studio album, Achtung Baby, at Berlin's Hansa Studios in October 1990 with producers Daniel Lanois and Brian Eno. The sessions were fraught with conflict, as the band argued over their musical direction and the quality of their material. While Clayton and Mullen preferred a sound similar to U2's previous work, Bono and the Edge were inspired by European industrial music and electronic dance music and advocated a change. Weeks of tension and slow progress nearly prompted the group to break up until they made a breakthrough with the improvised writing of the song "One". They returned to Dublin in 1991, where morale improved and the majority of the album was completed.
Achtung Baby was released in November 1991. The album represented a calculated change in musical and thematic direction for the group; the shift was one of their most dramatic since The Unforgettable Fire. Sonically, the record incorporated influences from alternative rock, dance, and industrial music of the time, and Bono referred to its musical departure as "four men chopping down the Joshua Tree". Thematically, it was a more introspective and personal record; it was darker, yet at times more flippant than the band's previous work. Commercially and critically, it has been one of the band's most successful albums. It produced five hit singles, including "The Fly", "Mysterious Ways", and "One", and it was a crucial part of the band's early 1990s reinvention. In 1993, Achtung Baby won the Grammy Award for Best Rock Performance by a Duo or Group with Vocal. Like The Joshua Tree, many publications have cited the record as one of rock's greatest. 
Question: What month and year was the band's seventh studio album released?
Output (English): November 1991.