question: Who was India's No. 1 player in both singles and doubles before their retirement, Frederik Nielsen or Sania Mirza?
answer: Sania Mirza
context: Title: Frederik Nielsen
  Passage: Frederik Løchte Nielsen (born 27 August 1983) is a professional male tennis player.  He is a former Wimbledon Men's Doubles champion, in 2012, and now competes mainly on the ATP Challenger Tour in both singles and doubles.  Nielsen is coached by fellow Dane John Larsen and is a member of the Denmark Davis Cup team.  His grandfather is former grand slam finalist Kurt Nielsen.
  Title: Olivia Rogowska
  Passage: Olivia Rogowska (born 7 June 1991) is an Australian professional tennis player.  Both of her parents are Polish.  The right-hander was born in and lives in Melbourne, Australia.  Her highest WTA singles ranking is 102, which she reached on 11 August 2014.  Her career high in doubles is 89, which she reached on 28 July 2014.  She has defeated Jelena Dokić, Alicia Molik, Maria Kirilenko and Sofia Arvidsson, and taken sets from former #1 Dinara Safina, Alona Bondarenko, Kateryna Bondarenko, Sorana Cîrstea, Jarmila Gajdošová, Anastasia Rodionova, Sania Mirza and Casey Dellacqua.
  Title: Vishnu Vardhan
  Passage: Vishnu Vardhan (born 27 July 1987), also known as J. Vishnuvardhan, is a professional tennis player from India, ranked in the top 300 on the ATP Tour as of 9 July 2012.  He was a member of the bronze medalist Indian men's team for 2010 Asian games in Guangzhou, China.  He paired-up with and Sania Mirza for mixed doubles and won silver medal.  He won the national singles title for the fourth time by winning the Men's final of Fenesta Open tennis Championship on October 8, 2016
  Title: 2017 St. Petersburg Ladies' Trophy – Doubles
  Passage: Martina Hingis and Sania Mirza were the defending champions, but Mirza chose not to participate this year.  Hingis played alongside Belinda Bencic, but lost in the first round to Gabriela Dabrowski and Michaëlla Krajicek.
  Title: Sania Mirza
  Passage: Sania Mirza (] ; born 15 November 1986) is an Indian professional tennis player who was formerly ranked No. 1 in the women's doubles rankings.  From 2003 until her retirement from singles in 2013, she was ranked by the Women's Tennis Association as India's No. 1 player, both in singles and doubles.  Throughout her career, Mirza has established herself as the most successful female Indian tennis player ever and one of the highest-paid and high-profile athletes in the country.
  Title: Tennis at the 2010 Asian Games – Mixed doubles
  Passage: At the 2010 Asian Games in the Mixed doubles tennis event, Sania Mirza and Leander Paes were the defending champions, but only Mirza participated, as Paes was involved in the Tour Finals.  Mirza partnered up with Vishnu Vardhan.  They went on to win the silver medal after losing to Chan Yung-jan and Yang Tsung-hua in the final 6–4, 1–6, [2–10].
citations: Sania Mirza Frederik Nielsen