What is the safest first-aid approach for a suspected snake bite in the field before professional care?

1. Keep the person calm and still, immobilise the bitten limb, and arrange rapid medical help without cutting or sucking the wound
2. Cut the wound and suck out venom with the mouth
3. Apply a tight arterial tourniquet as the only action and walk the person for exercise
4. Apply ice packs deep into the bite hole