Under standard visual separation rules on an active runway (ICAO Doc 4444), when may an Aerodrome Controller issue a landing clearance to a succeeding arriving aircraft?

1. As soon as the preceding landing aircraft has touched down, even if still at high speed on the runway
2. When the succeeding aircraft is at 10 NM on final approach regardless of preceding traffic
3. Only when the preceding landing aircraft has vacated the runway, or a preceding departing aircraft is airborne and has crossed the end of the runway (or turned away)
4. Whenever the succeeding pilot reports that they have the runway lights in sight