Question: Mary Pierce and Shelby Cannon, share which occupation?
Related documents: [0]  [DOC] Mary Pierce (born 15 January 1975) is a French retired tennis professional who played on the Women's Tennis Association (WTA) tour. Born in Canada, she is a citizen of Canada, and the United States. Pierce played for France in team competitions and in the Olympics. [END] 
[1]  [DOC] Shelby Cannon (born August 19, 1966, in Hattiesburg, Mississippi) is an American retired professional tennis player. [END] 
Answer: 
tennis professional
tennis professional