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:
| Year | Entrant | Chassis | Engine | Points |
| --- | --- | --- | --- | --- |
| 2006.0 | WilliamsF1 Team | Williams FW28 | Cosworth CA2006 2.4 V8 | 4 |
| 2007.0 | AT&T Williams | Williams FW29 | Toyota RVX-07 2.4 V8 | 20 |
| 2008.0 | AT&T Williams | Williams FW30 | Toyota RVX-08 2.4 V8 | 17 |
| 2009.0 | AT&T Williams | Williams FW31 | Toyota RVX-09 2.4 V8 | 34.5 |
| 2010.0 | Mercedes GP Petronas F1 Team | Mercedes MGP W01 | Mercedes FO 108X 2.4 V8 | 142 |
| 2011.0 | Mercedes GP Petronas F1 Team | Mercedes MGP W02 | Mercedes FO 108Y 2.4 V8 | 89 |
| 2012.0 | Mercedes AMG Petronas F1 Team | Mercedes F1 W03 | Mercedes FO 108Z 2.4 V8 | 93 |
| 2013.0 | Mercedes AMG Petronas F1 Team | Mercedes F1 W04 | Mercedes FO 108Z 2.4 V8 | 144* |
Question:
Which Chassis has 4 points?
Answer:
Williams FW28