What is the aerodrome controller's responsibility regarding jet blast and propeller wash hazards on taxiways and holding bays?

1. Controllers have no responsibility for jet blast; separation is entirely up to ground handlers
2. Controllers must direct all aircraft to taxi at maximum engine power to expedite movements
3. Controllers must ensure all aircraft shut down engines before taxiing behind other traffic
4. Controllers must exercise caution when clearing light aircraft to hold or taxi behind large jet aircraft and issue jet blast advisories when applicable