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:
| Driver | Entrant | Constructor | Time/Retired | Grid |
| --- | --- | --- | --- | --- |
| Peter Gethin | Yardley-BRM | BRM | 19:54.4 | 2.0 |
| Emerson Fittipaldi | Gold Leaf Team Lotus | Lotus - Cosworth | + 0.2 s | 3.0 |
| Jackie Stewart | Elf Team Tyrrell | Tyrrell - Cosworth | + 5.4 s | 6.0 |
| Jo Siffert | Yardley-BRM | BRM | + 12.8 s | 1.0 |
| Tim Schenken | Motor Racing Developments | Brabham - Cosworth | + 15.6 s | 7.0 |
| John Surtees | Team Surtees | Surtees - Cosworth | + 16.0 s | 10.0 |
| François Cevert | Elf Team Tyrrell | Tyrrell - Cosworth | + 24.8 s | 13.0 |
| Graham Hill | Motor Racing Developments | Brabham - Cosworth | + 31.6 s | 12.0 |
| Carlos Reutemann | Motor Racing Developments | Brabham - Cosworth | + 33.4 s | 11.0 |
| Alan Rollinson | Alan Rollinson | Surtees - Chevrolet | + 56.4 s | 17.0 |
| Frank Gardner | Motor Racing Research | Lola - Chevrolet | + 56.6 s | 14.0 |
| Mike Walker | Doug Hardwick | Lola - Chevrolet | + 58.0 s | 16.0 |
| Gordon Spice | Gordon Spice | McLaren - Chevrolet | + 1:10.2 s | 20.0 |
| Teddy Pilette | Racing Team VDS | McLaren - Chevrolet | + 1:11.4 s | 22.0 |
| Keith Holland | Keith Holland | McLaren - Chevrolet | + 1:12.2 s | 19.0 |
| Ronnie Peterson | STP March | March - Cosworth | + 1:15.8 s | 4.0 |
| Ray Allen | Team Trojan | McLaren - Chevrolet | 13 laps | 21.0 |
| Ian Ashley | Kaye Griffiths | Lola - Chevrolet | 13 laps | 24.0 |
| David Prophet | David Prophet Racing | McLaren - Chevrolet | 13 laps | 25.0 |
| Guy Edwards | J.T. Butterworth | McLaren - Chevrolet | 12 laps | 26.0 |
| Jackie Oliver | Bruce McLaren Motor Racing | McLaren - Cosworth | Brakes | 9.0 |
| Trevor Taylor | Malaya Garages | Leda - Chevrolet | Overheating | 23.0 |
| Howden Ganley | Yardley-BRM | BRM | Engine | 8.0 |
| Mike Hailwood | Team Surtees | Surtees - Cosworth | Suspension (collision) | 5.0 |
| Fred Saunders | Fred Saunders | Crosslé - Rover | Engine fire | 27.0 |
| Henri Pescarolo | Frank Williams Racing Cars | March - Cosworth | Collision | 15.0 |
| Reine Wisell | Sid Taylor | McLaren - Chevrolet | Collision | 18.0 |
Question:
What constructor has a grid less than 21, and time/retired of engine?
Answer:
BRM