Answer:
D. an increase in the number of hijackings worldwide.
Step-by-step explanation:
Out of the options presented, the only one that was not a result of the attacks of 9/11 or The War on Terror was an increase in the number of hijackings worldwide. Not only were hijackings as rare as before, but no major attempts to carry one out were found. This most likely supports the conclusion that the terrorist attack of 9/11 was an anomaly. In turn, this brings into question whether increased security at airports or the War on Terror itself was necessary.