Private airline companies have always been determined to operate a transport system that is safe for passengers, whilst still remaining competitively priced and commercially viable. However, a private sector business can only remain viable if it generates profits for its shareholders. Recent reports suggest that if all aircrafts were fitted with military derived ground-to-air missile defense system, and at all airports there was infallible screening for weapons and explosives then the system would be much safer. However, totally effective screening would preclude all possibility of profit, and current systems are still very thorough, whilst also providing a good cost-benefit ratio.

Question: Current airline security systems provide the best possible mix of cost against benefit.
Options:
A. true, B. false, C. uncertain
Answer: "C"