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:
| Model | Built | Quantity | Seats | Length | Engine |
| --- | --- | --- | --- | --- | --- |
| PG-2501 | 1939–1940 | 8.0 | 25.0 | ft1in (m) | GMC 248 6 cyl. gas |
| PG-2502 | 1939–1940 | 66.0 | 25.0 | ft1in (m) | GMC 308 6 cyl. gas |
| PG-2503 | 1941 | 4.0 | 25.0 | ft1in (m) | GMC 248 6 cyl. gas |
| PG-2504 | 1940–1941 | 70.0 | 25.0 | ft1in (m) | GMC 308 6 cyl. gas |
| PG-2505 | 1941–1942 | 118.0 | 25.0 | ft1in (m) | GMC 308 6 cyl. gas |
| PG-2901 | 1939–1940 | 50.0 | 29.0 | ft0in (m) | GMC 426 6 cyl. gas |
| PD-2901 | 1939–1940 | 16.0 | 29.0 | ft0in (m) | GMC 4-71 4 cyl. diesel |
| PG-2902 | 1940–1941 | 56.0 | 29.0 | ft0in (m) | GMC 426 6 cyl. gas |
| PD-2902 | 1941–1942 | 249.0 | 29.0 | ft0in (m) | GMC 4-71 4 cyl. diesel |
| PG-2903 | 1941–1942 | 304.0 | 29.0 | ft0in (m) | GMC 426 6 cyl. gas |
| PD-3301 | 1942 | 115.0 | 33.0 | ft0in (m) | GMC 4-71 4 cyl. diesel |
| PG-3301 | 1942–1943 | 49.0 | 33.0 | ft0in (m) | GMC 477 6 cyl. gas |
| PD-3701 | 1940–1941 | 59.0 | 37.0 | ft0in (m) | GMC 6-71 6 cyl. diesel |
| PDG-3701 | 1940–1941 | 240.0 | 37.0 | ft0in (m) | GMC 6-71 6 cyl. diesel |
| PG-3701 | 1940–1941 | 70.0 | 37.0 | ft0in (m) | GMC 707 6 cyl. gas |
| PGG-3701 | 1940–1941 | 91.0 | 37.0 | ft0in (m) | GMC 707 6 cyl. gas |
| PDA-3701 | 1942–1943 | 185.0 | 37.0 | ft0in (m) | GMC 4-71 4 cyl. diesel |
| PGA-3701 | 1942–1943 | 51.0 | 37.0 | ft0in (m) | GMC 477 6 cyl. gas |
| PDG-4101 | 1940–1941 | 224.0 | 41.0 | ft0in (m) | GMC 6-71 6 cyl. diesel |
| PGG-4101 | 1940–1941 | 35.0 | 41.0 | ft0in (m) | GMC 707 6 cyl. gas |
Question:
What is the Quantity of the engine Model PG-2901?
Answer:
50.0