Arrival operations dictate that an aircraft or vehicle must complete crossing before what happens?

In arrival operations, it is crucial that an aircraft or vehicle completes crossing a specified point, such as a runway or taxiway, before an aircraft lands. This is because safety protocols are in place to ensure that the runway is clear of any obstacles or personnel before a landing occurs. If an aircraft were to land while another is still crossing the runway, it could lead to a catastrophic collision. Thus, the completion of crossing is a precondition to maintain safe operational procedures and ensure that all arrivals and departures occur without endangering any vehicles or personnel on the ground.

The other options suggest various activities related to aircraft movements, but only the landing is contingent on the clear completion of crossing the specified point to ensure a safe approach.