18. Drones have become an increasing nuisance for airports worldwide in recent months, and good solutions to keeping themfrom interfering with flights aren’t yet available. Airports in various cities have grounded planes in the last three monthsfollowing drone sightings. The incident at Gatwick in December proved especially disruptive, _____. Aviation experts fearcatastrophic damage or death could result from a drone hitting an airplane. Such an incident could be accidental ormotivated by ill will, such as a terrorist attack.
(A) impacting the flights of more than 100,000 passengers
(B) losing millions of dollars from flight delays and cancellations
(C) causing more damage than birds—a threat the industry has long faced
(D) concerning the lack of fully vetted drone detection and counterdrone systems