請依下文回答第 51 題至第 55 題：
      Would Covid masks help criminals get away with it? It was the question posed by police,academics and many others when face coverings became __51__ in shops and other places last year.Now, it seems, they have their answer as Kent police in the UK say catching a person guilty of a crimehas become even __52__ as putting together an accurate efit (electronic facial identification technique)–which officers use like wanted posters – is difficult when the person __53__ is wearing a mask. SusanMorrison, a civil supervisor at Kent police’s identification office, said, “We are seeing an increase inreports of guilty people wearing masks. And while we view each case separately, sometimes it can bemore stressful for the victim to go through the process of making an efit, than the result is useful to theinvestigation.” The phenomenon is __54__ limited to the UK. US media outlets have reports on a couplein Connecticut committed a series of crime in a day, during which they are accused of robbing severalshops while disguised in medical masks. In order to __55__ an increase in mask-assisted crime,professors at Leeds University’s law school warned shop owners to look out for robbers returning for asecond bite of the cherry. This is because they know that successful commercial robbers return to the same,nearby or same-type places.
【題組】51
(A) essential
(B) memorial
(C) beneficial
(D) imperial