What will happen if the air vent hole in the fuel tank cap becomes completely blocked with dirt or debris?

1. A vacuum will form inside the fuel tank as fuel is consumed, eventually stopping fuel flow and causing the engine to stall.
2. The fuel tank will swell and deform due to high internal air pressure.
3. Fuel will pump out of the carburetor overflow tube at twice the normal speed.
4. The engine will run excessively rich because the fuel is pressurized.