Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Event | Time | Nationality | Date | Meet | Location |
| --- | --- | --- | --- | --- | --- |
| 50m freestyle | 20.91 | Brazil | 18 December 2009 | Brazilian Championships | São Paulo , Brazil |
| 100m freestyle | 46.91 | Brazil | 30 July 2009 | World Championships | Rome , Italy |
| 200m freestyle | 1:42.96 | United States | 12 August 2008 | Olympic Games | Beijing , China |
| 400m freestyle | 3:42.78 | United States | 10 August 2008 | Olympic Games | Beijing , China |
| 800m freestyle | 7:41.86 | Canada | 27 July 2011 | World Championships | Shanghai , China |
| 1500m freestyle | 14:39.63 | Canada | 4 August 2012 | Olympic Games | London , United Kingdom |
| 50m backstroke | 24.33 | United States | 5 December 2008 | Dutch Swim Cup | Eindhoven , Netherlands |
| 100m backstroke | 51.94 | United States | 8 July 2009 | US Championships | Indianapolis , United States |
| 200m backstroke | 1:51.92 | United States | 31 July 2009 | World Championships | Rome , Italy |
| 50m breaststroke | 26.76 | Brazil | 29 July 2009 | World Championships | Rome , Italy |
| 100m breaststroke | 58.96 | United States | 26 July 2009 | World Championships | Rome , Italy |
| 200m breaststroke | 2:07.42 | United States | 30 July 2009 | World Championships | Rome , Italy |
| 50m butterfly | 22.76 | Brazil | 26 April 2012 | Maria Lenk Trophy | Rio de Janeiro , Brazil |
| 100m butterfly | 49.82 | United States | 1 August 2009 | World Championships | Rome , Italy |
| 200m butterfly | 1:51.51 | United States | 29 July 2009 | World Championships | Rome , Italy |
| 200m individual medley | 1:54.00 | United States | 28 July 2011 | World Championships | Shanghai , China |
| 400m individual medley | 4:03.84 | United States | 10 August 2008 | Olympic Games | Beijing , China |
| 4×100m freestyle relay | 3:08.24 | United States | 11 August 2008 | Olympic Games | Beijing , China |
| 4×200m freestyle relay | 6:58.55 | United States | 31 July 2009 | World Championships | Rome , Italy |
| 4×100m medley relay | 3:27.28 | United States | 2 August 2009 | World Championships | Rome , Italy |
Question:
What event is on 18 December 2009?
Answer:
50m freestyle