Why should one avoid running the vehicle's engine in a closed place?

1. AIn order to prevent the engine from overheating, due to lack of sufficient ventilation.
2. BThere is no need to avoid it. It makes no difference whether the engine runs in a closed place or in an open place.
3. CBecause it is not possible to run the engine in a closed place.
4. DBecause the exhaust gases emitted from the engine are toxic to humans.

Pick an answer to test yourself