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:
| Source | Date | Jody Wagner | Pat Edmonson | Michael Signer | Rich Savage | Jon Bowerbank | Undecided |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Public Policy Polling | June 6–7, 2009 | 41% | n/a | 12% | n/a | 6% | 42% |
| Suffolk University | June 4, 2009 | 30% | n/a | 7% | n/a | n/a | 62% |
| Public Policy Polling | May 28–31, 2009 | 27% | n/a | 11% | n/a | n/a | 63% |
| Public Policy Polling | May 19–21, 2009 | 21% | n/a | 11% | n/a | n/a | 68% |
| Public Policy Polling | May 1–3, 2009 | 18% | n/a | 7% | n/a | 6% | 69% |
| Public Policy Polling | March 27–29, 2009 | 21% | 4% | 4% | n/a | 4% | 67% |
| Public Policy Polling | February 28–March 1, 2009 | 9% | 6% | 5% | 4% | 3% | 73% |
Question:
On which date did Michael Signer earn 4%?
Answer:
March 27–29, 2009