What is a primary symptom and cause of a gas turbine engine compressor stall?

1. A loud bang and rapid rise in Exhaust Gas Temperature (EGT), caused by the disruption of airflow through the compressor blades.
2. A sudden drop in engine RPM accompanied by ice formation on the inlet guide vanes.
3. A slow decay in fuel pressure accompanied by blue smoke from the exhaust.
4. The engine accelerating past its maximum rotational speed limit due to a governor failure.