Question: Released at the height of a five-decade recording career, and featuring the single "If I Could Turn Back Time," Heart of Stone was what number album for Cher?  

Context paragraphs:
The Very Best of Cher: The Very Best of Cher is the eighth compilation album by American singer-actress Cher, released on April 1, 2003.  The album includes many of Cher's most popular songs, such as "If I Could Turn Back Time", "Believe", "Gypsies, Tramps and Thieves" and "Take Me Home".  It debuted at number seven on the "Billboard" 200 albums chart and later reached number four on the issue date of May 17.  As of November 2011, the album had sold 2.8 million copies in the United States.

If I Could Turn Back the Hands of Time: "If I Could Turn Back the Hands of Time" is a song by R. Kelly, released as the fifth single from his 1998 album, "R.".  The song is a sweeping ballad about a man wishing he could go back in time and repair his relationship with his girlfriend.  The song was a top 10 hit on the pop charts of several countries, while in the United States it finished just outside the top 10, peaking at number 12.

The Very Best of Cher: The Video Hits Collection: The Very Best of Cher: The Video Hits Collection is a collection of 15 of Cher's greatest music videos.  The anthology includes the popular "Believe" and "If I Could Turn Back Time" as well as the obscure "Main Man".

Tidal Wave (Sub Focus song): "Tidal Wave" is the third single by British DJ and record producer Sub Focus to be released from his second studio album "Torus".  The song features vocals from Alpines.  The song peaked at number 12 on the UK Singles Chart and number 4 on the UK Dance Chart, making it his highest-charting single until "Endorphins" and "Turn Back Time", which both peaked at number 10 on the UK Singles Chart.  It is still his highest-charting single on the UK Dance Chart and his biggest-selling single.

If I Could Turn Back Time: "If I Could Turn Back Time" is a song recorded by American singer and actress Cher.  Written by Diane Warren and co-produced along with Guy Roche, the pop rock track was included on Cher's nineteenth album, "Heart of Stone" (1989).  The song was released on June 1, 1989 as the second North American and first European single release from the album.  The song also appears on the greatest hits compilations "The Greatest Hits" (1999) and "The Very Best of Cher" (2003).  In 1989, it was certified Gold by the RIAA for the sales of 500,000 copies.  Sales haven't been updated since.  In November 2011, Billboard reported the digital sales of "If I Could Turn Back Time" to be 394,000 in the US.

Cher: Cher ( ; born Cherilyn Sarkisian; May 20, 1946) is an American singer and actress.  Sometimes referred to as the Goddess of Pop, she has been described as embodying female autonomy in a male-dominated industry.  She is known for her distinctive contralto singing voice and for having worked in numerous areas of entertainment, as well as adopting a variety of styles and appearances during her five-decade-long career.

If I Could Turn Back Time: Cher's Greatest Hits: If I Could Turn Back Time: Cher's Greatest Hits is the fourth U.S. compilation album by American singer-actress Cher, released on March 9, 1999 by Geffen.  In January 2000, the album was certified Gold by the RIAA for selling more than 500,000 copies in the US.  Billboard stated in November 2011 that the album has sold 955,000 copies in the US.  It does not contain her last 1998 worldwide hit "Believe".

Guy Roche: Guy Roche is a record producer and songwriter who is best known for the hit singles he has co-written/co-produced for Christina Aguilera, which include but are not limited to "What a Girl Wants", "I Turn to You", and "Come On Over Baby (All I Want Is You).  He also co-wrote Brandy's "Never Say Never" single "Almost Doesn't Count" (along with Shelly Peiken).  He also produced Selena's song "Dreaming Of You", included on Selena's last album "Dreaming of You".  He has also written and produced songs for Aaliyah, Gladys Knight, Natasha Bedingfield, Brandy, Xscape, RBD, Cher (including her #3 Billboard hit "If I Could Turn Back Time"), Celine Dion, Chimène Badi and Dru Hill.

Turn Back the Hands of Time: "Turn Back the Hands of Time" is a song recorded by American R&B singer Tyrone Davis.  The song was co-written by Jack Daniels and Bonnie Thompson and produced by Willie Henderson.  Daniels and Thompson wrote "Turn Back the Hands of Time" based on the relationship problems that Daniels was having at the time.  Daniels had co-written Davis's 1968 hit "Can I Change My Mind" and the recording session for "Turn Back the Hands of Time" included some of the same musicians from "Can I Change My Mind".  "Turn Back the Hands of Time" was released as a single in February 1970 and became Davis's second major hit, spending two weeks at number one on Billboard's R&B Singles chart and reaching number three on its Pop chart.  The single was also certified gold by the RIAA for sales of one million copies.  "Turn Back the Hands of Time" is from the album of the same name that MTV says "ranks among the best soul LP's of its time".

Turn Back Time (TV series): Turn Back Time (originally titled If I Could Turn Back Time) is a British television series produced by Hat Trick Productions for BBC One.  It aired from 9 August to 13 September 2006, and was hosted by Dara Ó Briain.  In the show, famous faces revealed what they regret doing, and not doing, in their life.

Supporting paragraphs: If I Could Turn Back Time Cher
Answer: nineteenth