An unpressurized aircraft flies above 13,000 feet ASL cabin-pressure-altitude. For whom must oxygen be available?

1. 1The crew only
2. 2All persons on board, for the whole period at that altitude
3. 3The pilot-in-command only
4. 410 per cent of the passengers only

Source: Canadian Aviation Regulations (SOR/96-433), CAR 605.31(1) Oxygen Equipment and Supply