Question: For how many weeks has the athlete who defended her title in the 2007 Acura Classic-Singles been ranked world No 1 by the WTA?

Context paragraphs:
2007 Sports Car Challenge of Mid-Ohio: The 2007 Acura Sports Car Challenge of Mid Ohio was the seventh round of the 2007 American Le Mans Series season.  It took place at the Mid-Ohio Sports Car Course on July 21, 2007.

2007 Acura Classic: The 2007 Acura Classic was a tennis tournament played on outdoor hard courts in San Diego in the United States.  It was part of Tier I of the 2007 WTA Tour.  The tournament was held from July 30 through August 5, 2007.

Elena Dementieva: Elena Viacheslavovna Dementieva (Russian: Еле́на Вячесла́вовна Деме́нтьева , ] ; born 15 October 1981) is a retired Russian tennis player.  Dementieva won the singles gold medal at the 2008 Olympics in Beijing, having previously won the silver medal at the 2000 Olympics in Sydney.  She won 16 WTA singles titles, reached the finals of the 2004 French Open and 2004 US Open and reached seven other Grand Slam semi finals.  Dementieva was also part of the Russian team that won the 2005 Fed Cup, won the 2002 WTA Championship doubles with Janette Husárová and was the runner-up in two US Open doubles finals – in 2002 with Husárová and in 2005 with Flavia Pennetta.  Dementieva achieved a career-high ranking of World No. 3, which was accomplished on 6 April 2009.  She announced her retirement on 29 October 2010, after her final match at the 2010 WTA Tour Championships.  Dementieva ended her career ranked World No. 9 and between 2003 and 2010 she only ended one year, in 2007, outside the top 10.

2007 Acura Classic – Singles: Maria Sharapova successfully defended her title, by defeating Patty Schnyder in the final.

2007 Sports Car Challenge of St. Petersburg: The 2007 Acura Sports Car Challenge of St. Petersburg was the second round of the 2007 American Le Mans Series season.  It took place on March 31, 2007.

Acura TL: The Acura TL is a mid-size luxury car that was manufactured by Acura.  It was introduced in 1995 to replace the Acura Vigor and was badged for the Japanese-market from 1996 to 2000 as the Honda Inspire and from 1996 to 2004 as the Honda Saber.  The TL was Acura's best-selling model until it was outsold by the MDX in 2007.  While it once ranked as the second best-selling luxury sedan in the United States behind the BMW 3 Series, sales have decreased by over 50% since then.  TL sales have been negatively affected by both the recession as well as negative publicity due to styling issues in the latest generation.  Four generations of the Acura TL were produced, with the final fourth generation TL premiering in 2008 as a 2009 model and ending production in 2014, when it was replaced together with the TSX by the TLX.  In its last year, the TL was sold in Japan.

Martina Hingis: Martina Hingis (born 30 September 1980) is a Swiss professional tennis player, a former world No. 1 singles player and currently ranked world No. 2 in doubles by the WTA.  She has spent a total of 209 weeks as the singles No. 1 and has won five Grand Slam singles titles, thirteen Grand Slam women's doubles titles, winning a calendar-year doubles Grand Slam in 1998, and seven Grand Slam mixed doubles titles; for a combined total of twenty-five major titles.  In addition, she has won the season-ending WTA Championships two times in singles and three times in doubles, and an Olympic silver medal.

List of WTA number 1 ranked tennis players: The list of WTA number 1 ranked players shows the professional women's tennis players who have been or currently are ranked world No. 1 by the Women's Tennis Association, along with the dates of first reaching and losing that spot.  Since the WTA began producing computerized rankings on November 3, 1975, 24 women have reached the highest singles ranking and 35 women the highest doubles ranking.  The WTA Rankings are a merit-based method for determining the rankings in women's tennis and the WTA releases ranking points weekly based on how players fared during the previous 52 weeks.

Caroline Wozniacki career statistics: This is a list of the main career statistics of professional Danish tennis player Caroline Wozniacki.  To date, Wozniacki has won twenty-six WTA singles titles including two WTA Premier Mandatory singles titles and three WTA Premier 5 singles titles.  She was also the runner-up at the 2009 US Open, 2010 WTA Tour Championships, and 2014 US Open, a semi-finalist at the 2010 US Open, 2011 Australian Open and 2011 US Open and a quarterfinalist at the 2010 French Open and 2012 London Olympics.  Wozniacki was first ranked World No. 1 by the Women's Tennis Association (WTA) on October 11, 2010.

Maria Sharapova: Maria Yuryevna Sharapova (Russian: Мари́я Ю́рьевна Шара́пова ; ] ; born April 19, 1987) is a Russian professional tennis player.  A United States resident since 1994, Sharapova has competed on the WTA tour since 2001.  She has been ranked world No. 1 in singles by the WTA on five separate occasions, for a total of 21 weeks.  She is one of ten women, and the only Russian, to hold the career Grand Slam.  She is also an Olympic medalist, having earned silver for Russia in women's singles at the 2012 Summer Olympics in London.

Supporting paragraphs: 2007 Acura Classic – Singles Maria Sharapova
Answer: 21