Final answer:
Parallel runways with enough separation allow for simultaneous arriving and departing if visual separation can be maintained, ensuring aircraft safety.
Step-by-step explanation:
The question pertains to the rules governing the use of parallel runways in an airport setting during simultaneous arriving and departing operations. The correct response to the question is that simultaneous arriving and departing operations may be authorized when visual separation can be maintained. This means air traffic controllers must be able to visually confirm that the aircraft operating on the parallel runways are separated by a safe distance at all times. During times when visibility is inadequate, such as during inclement weather or nighttime, other methods than visual separation alone must be used to ensure safety.