Which of the following tennis players is the only one among the four who won all four major tournaments?

Maria Sharapova of Russia has won all four major tennis tournaments throughout the span of her career. She won Wimbledon in 2004, the US Open in 2006, the Australian Open in 2008, and the French Open in 2012 and 2014 making her major tournament trophy count to five.

Venus Williams has never won the Australian Open and the French Open. Martina Hingis had never won the French Open. Monica Seles had not won Wimbledon. Nevertheless, Williams has seven major tournament wins, Hingis has five - same as Sharapova, and Seles has nine.