Which of the following activities MUST be recorded under the 'Other Work' (crossed hammers icon) symbol on the digital tachograph under Article 6(5) of Regulation (EC) No 561/2006 and Directive 2002/15/EC?

1. Loading, unloading, securing cargo, cleaning the vehicle, performing pre-trip inspections, and handling customs clearance documents
2. Sitting in the passenger seat while a second driver operates the vehicle in a team
3. Sleeping in the sleeper berth while the vehicle is parked at a service area
4. Waiting at home on standby when not required to remain at the workstation