阅读下列短文，从每题所给的四个选项(A、B、C和D)中，选出最佳选项。

　　Clean your ears, because airport security might soon be scanning them．According to a recent discovery, the shape of ears could provide a reliable new way of identifying people at airports．

　　Researchers discovered that ears of each person have a unique shape and they have created a system that can scan them．The ear scanning technique uses a technology called image ray transform that highlights all the tubular structures(结构)of the ear and measures them．Professor Mark Nixon, a computer scientist who led the team from the University of Southampton, believes ear scanning could take place as passengers walk through security gates, for example, by placing cameras on either side to record an image of their ears．Comparing the results against a database of ear shapes, the new system could help airport security workers instantly identify passengers．

　　Nixon and his team tested 252 images of different ears and found the system was able to match each ear to a separate image held in its database with 99 percent accuracy．

　　Besides ear scanning, there have been other systems developed for identity recognition．

　　“With facial recognition, the systems are often confused by crows feet(鱼尾纹)and other signs of ageing,” Nixon said． “Your ears, however, age very gracefully．They grow proportionally(按比例)and your lobe(耳垂)gets a bit larger, but otherwise your ears are fully formed from birth．” What's more, facial recognition software is often confused by changes in expression so people need to control their faces and in some cases even avoid wearing make－up．

　　An ear scan system would also offer a less invasive alternative to retina(视网膜)scanning, which requires passengers to stare at scanners from a close range．

　　Fingertip detection has long been the most effective way of identifying someone．Nixon expects there to be a combination of different techniques that can be used at the same time to identify a person．”