In a two-driver coach operation, how is the time spent by the second driver sitting next to the driver in the moving coach classified on the digital tachograph?

1. As 'Driving time' (Lenkzeit)
2. As 'Availability' (Bereitschaftszeit - symbol: square box with diagonal slash/box), provided the co-driver is not actively assisting with passenger service or ticket checking
3. As 'Regular daily rest' (Tägliche Ruhezeit - bed symbol)
4. As 'Other work' (Andere Arbeiten - crossed hammers)