Question: The singles title at the 1987 Lorraine Open was won by a player whose career high ranking was at what number?
Context: Sophie Ferguson (born 19 March 1986, in Sydney) is a former Australian professional tennis player.  Ferguson has won nine ITF Women's Circuit titles and has played on the WTA Tour.  She reached a career high ranking in singles of World number 109 on 19 July 2010.  High ranking in doubles of World number 148 on 8 October 2007.  She retired from tennis in 2012. Ben Taylor-Matthews (born 27 July 1984) is a professional British Real Tennis player based at Leamington Tennis Court Club, in Warwickshire.  His career high ranking is world number 5, which is also his current ranking.  As of June 2016 he is also the British number 1.  To date he is yet to win a major singles title, but has contested two Australian Open finals.  in 2010 he won the US Open doubles championship, partnered by Steven Virgona.  In 2012 he qualified for the World Championship, the sports biggest prize, which taes only the top four players over a two-year period leading up to the challenge itself. Francesca Schiavone (] ; born 23 June 1980 in Milan) is an Italian tennis player who turned professional in 1998.  She won the 2010 French Open singles title, becoming the first Italian woman to win a Grand Slam event in singles.  She was also runner-up at the 2011 French Open.  Her career high ranking is world No. 4, achieved on 31 January 2011.  To date, Schiavone is the last one handed-backhand player to win a Grand Slam title on the women's tour. Alexandra Nancarrow (born 1 September 1993 in Canberra) is an Australian tennis player.  Nancarrow has a WTA singles career high ranking of 385 achieved on 10 November 2014.  She also has a WTA doubles career high ranking of 346 achieved on 2 February 2015.  Nancarrow has won 2 ITF singles title as well as 16 ITF doubles titles. Ingrid Gamarra Martins (born 22 August 1996 in Rio de Janeiro) is a Brazilian tennis player.  Gamarra Martins has a WTA singles career high ranking of 781 achieved on 6 April 2015.  She also has a WTA doubles career high ranking of 524 achieved on 6 April 2015. Félix Auger-Aliassime (born August 8, 2000) is a Canadian professional tennis player.  He reached a career high ATP singles ranking of No. 161 on September 18, 2017 and a career high ITF junior ranking of No. 2 on June 6, 2016.  He is the youngest player ever to qualify and to win a main draw match on the ATP Challenger Tour.  With his titles at the Open Sopra Steria de Lyon in June 2017 and the Copa Sevilla in September 2017, he became the seventh youngest player in history (16 years, 10 months) to win an ATP Challenger title and the second youngest to win multiple ATP Challenger titles.  Auger-Aliassime won the 2016 US Open junior singles title and the 2015 US Open junior doubles title with compatriot Denis Shapovalov. Gaia Sanesi (born 1 April 1992 in Florence) is an Italian tennis player.  Sanesi has a WTA singles career high ranking of 294 achieved on 14 July 2014.  She also has a WTA doubles career high ranking of 437 achieved on 3 March 2014.  Sanesi has won 2 ITF singles titles as well as 1 ITF doubles title. Rohan Bopanna (born 4 March 1980) is an Indian professional tennis player.  His singles career high ranking was World No. 213 in 2007 and his career high ranking in doubles was World No. 3 on 22 July 2013.  Recently, most of his appearances in professional tournaments have been in doubles matches.  He is a member of the Indian Davis Cup team since 2002.  In 2010, he finished as a runner-up in doubles at the US Open, partnering with Aisam-ul-Haq Qureshi.  He won the 2017 French Open - Mixed Doubles title with Gabriela Dabrowski of Canada becoming the fourth Indian player to win a Grand Slam title. The 1987 Lorraine Open was a men's tennis tournament played on indoor carpet courts in Nancy, France, and was part of the 1987 Nabisco Grand Prix.  It was the ninth edition of the tournament took place from 23 March through 29 March 1987.  First-seeded Pat Cash won the singles title. Patrick Hart Cash (born 27 May 1965) is a retired Australian professional tennis player.  He reached a career-high ATP singles ranking of world No. 4 in May 1988 and a career-high ATP doubles ranking of world No. 6 in August 1988.  He has been described as one of the greatest net players of all time.  After winning the men's singles championship at Wimbledon in 1987, he climbed into the stands to celebrate, starting a tradition which has been followed by many winners in subsequent years.
Answer: No. 4