Question: Ilie Năstase and Shelby Cannon, have which mutual occupation?
Context: The 1972 Monte Carlo Open was a men's tennis tournament played on outdoor clay courts at the Monte Carlo Country Club in Monte Carlo, Monaco .  The tournament was part of the WCT Tour, which was incorporated into the 1972 Commercial Union Assurance Grand Prix circuit.  It was the 66th edition of the event and was held from 27 March through 3 April 1972.  Ilie Năstase won the singles title. Mihnea-Ion Năstase (born 7 February 1967) is a former professional tennis player from Romania.  He is a nephew of two-time Grand Slam winner Ilie Năstase and his father, Constantin Năstase, was a Romanian Davis Cup representative. The 2014 BRD Năstase Țiriac Trophy was a tennis tournament played on outdoor clay courts and held at Arenele BNR in Bucharest, Romania, from 21 to 27 April 2014.  It was the 22nd edition of the BRD Năstase Țiriac Trophy tournament, and was part of the ATP World Tour 250 Series of the 2014 ATP World Tour.  The event also futured an exhibition match with Goran Ivanišević, Cédric Pioline, Ilie Năstase and Andrei Pavel. The Romanian Open (also known as the BRD Năstase Țiriac Trophy) was a professional men's tennis tournament played on outdoor clay courts.  It was part of the ATP World Tour 250 series of the ATP Tour.  It was held annually in Bucharest, Romania, since 1993.  Its name is taken from Romania's famous tennis players Ilie Năstase and Ion Țiriac. Ilie "Nasty" Năstase (] , born 19 July 1946) is a Romanian former world No. 1 professional tennis player, one of the world's top players of the 1970s.  He was ranked world no. 1 from 23 August 1973 to 2 June 1974. The 1973 Queen's Club Championships was a tennis tournament played on grass courts at the Queen's Club in London in the United Kingdom.  The men's tournament was part of the 1973 Commercial Union Assurance Grand Prix circuit while the women's event was part of the 1973 Women's Grand Prix tour.  It was the 74th edition of the tournament and was held from June 17 through June 23, 1973.  Ilie Năstase and Olga Morozova won the singles titles. Shelby Cannon (born August 19, 1966, in Hattiesburg, Mississippi) is an American retired professional tennis player. The 1971 Monte Carlo Open was a combined men's and women's tennis tournament played on outdoor clay courts at the Monte Carlo Country Club in Monte Carlo, Monaco .  The men's tournament was part of the 1971 Pepsi-Cola Grand Prix circuit.  It was the 65th edition of the event and was held from 5 April through 11 April 1971.  Ilie Năstase and Gail Chanfreau won the singles titles. The 1973 Monte Carlo Open, also known by its sponsored name Craven Monte Carlo Championships, was a men's tennis tournament played on outdoor clay courts at the Monte Carlo Country Club in Monte Carlo, Monaco .  The tournament was part of the Rothmans Spring Mediterranean Circuit, a series of six tournaments held in France, Monaco, Spain and Italy from March to May 1973.  It was the 67th edition of the event and was held from 16 April through 21 April 1973.  Ilie Năstase won the singles title. Brad Gilbert and Ilie Năstase were the defending champions, but Năstase did not participate this year.  Gilbert partnered Shlomo Glickstein, losing in the first round.
Answer: professional tennis player