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 |
| --- | --- | --- | --- | --- |
| 1952.0 | Equipe Gordini | Gordini Type 16 | Gordini Straight-6 | 6 |
| 1953.0 | Equipe Gordini | Gordini Type 16 | Gordini Straight-6 | 0 |
| 1954.0 | Equipe Gordini | Gordini Type 16 | Gordini Straight-6 | 1⁄7 |
| 1955.0 | Officine Alfieri Maserati | Maserati 250F | Maserati Straight-6 | 6 |
| 1956.0 | Officine Alfieri Maserati | Maserati 250F | Maserati Straight-6 | 22 |
| 1957.0 | Officine Alfieri Maserati | Maserati 250F | Maserati Straight-6 | 6 |
| 1957.0 | Officine Alfieri Maserati | Maserati 250F | Maserati V12 | 6 |
| 1958.0 | Ken Kavanagh | Maserati 250F | Maserati Straight-6 | 9 |
| 1958.0 | Owen Racing Organisation | BRM P25 | BRM Straight-4 | 9 |
| 1959.0 | Scuderia Ferrari | Ferrari Dino 246 | Ferrari V6 | 2 |
| 1959.0 | Jean Behra | Behra-Porsche RSK | Porsche Flat-4 | 2 |
Question:
What is the entrant of a chassis maserati 250f, also has 6 points and older than year 1957?
Answer:
Officine Alfieri Maserati