Years ago, I was watching a detective show on TV where the fingerprints of a criminal are required. The hero invites the bad guy to his home and offers him a glass of water. The man takes the glass and drinks the water. After he leaves the hero dramatically brings out a handkerchief and picks up the glass. His expressions show the satisfaction at a job well done. The bad guy will soon be arrested.  At that time, I found it amazing - how can prints on a glass identify people? My dad explained that if you were to press your thumb on an inkpad and then on a sheet of white paper you will leave a smudge or print, which no one else in the world can make. The same would be true for each of your fingers. The Chinese were the first to use a fingerprint as a type of identification - it was used as a signature on important documents, although they had no way of independently matching it with the owner.  Each print is one-of-a-kind and no two people have the same characteristic. Scientists and criminologists (those who study criminal characteristics) determine the differences between fingerprints by a careful study of their curves and not by their general shape or pattern.  In 1892, an English scientist, Sir Francis Galton, published a book on using fingerprints to solve crimes. At the same time in Argentina, a police researcher Juan Vucetich was also working towards a fingerprint classification system. However, it was in 1896 that Sir Edward Henry, then serving as Inspector General of Police in India, developed the print classification system that would eventually be used globally.  Sir Edward Henry and his assistant Khan Haque discovered that all fingerprints could be systematically classified according to their general curve patterns. He divided them into three classes on the basis of their general pattern: loops  , whorls  , and arches  . By counting the curve between any two points in the pattern, each of the ten fingers could be classified into a particular group. Taking the group together as a unit you have a complete system of classifying fingerprints.  In June 1897, the world's first fingerprint bureau was set up in Calcutta and in 1901, Sir Edward Henry was appointed head of Scotland Yard in London, where he applied the system. This system, called the science of fingerprint identification, is still used by police departments all over the world today with few changes. Fingerprints were first used in China to   _  .
sign documents capture criminals show respect prove identity
Question: Years ago, I was watching a detective show on TV where the fingerprints of a criminal are required. The hero invites the bad guy to his home and offers him a glass of water. The man takes the glass and drinks the water. After he leaves the hero dramatically brings out a handkerchief and picks up the glass. His expressions show the satisfaction at a job well done. The bad guy will soon be arrested.  At that time, I found it amazing - how can prints on a glass identify people? My dad explained that if you were to press your thumb on an inkpad and then on a sheet of white paper you will leave a smudge or print, which no one else in the world can make. The same would be true for each of your fingers. The Chinese were the first to use a fingerprint as a type of identification - it was used as a signature on important documents, although they had no way of independently matching it with the owner.  Each print is one-of-a-kind and no two people have the same characteristic. Scientists and criminologists (those who study criminal characteristics) determine the differences between fingerprints by a careful study of their curves and not by their general shape or pattern.  In 1892, an English scientist, Sir Francis Galton, published a book on using fingerprints to solve crimes. At the same time in Argentina, a police researcher Juan Vucetich was also working towards a fingerprint classification system. However, it was in 1896 that Sir Edward Henry, then serving as Inspector General of Police in India, developed the print classification system that would eventually be used globally.  Sir Edward Henry and his assistant Khan Haque discovered that all fingerprints could be systematically classified according to their general curve patterns. He divided them into three classes on the basis of their general pattern: loops  , whorls  , and arches  . By counting the curve between any two points in the pattern, each of the ten fingers could be classified into a particular group. Taking the group together as a unit you have a complete system of classifying fingerprints.  In June 1897, the world's first fingerprint bureau was set up in Calcutta and in 1901, Sir Edward Henry was appointed head of Scotland Yard in London, where he applied the system. This system, called the science of fingerprint identification, is still used by police departments all over the world today with few changes. Fingerprints were first used in China to   _  .
A. sign documents
B. capture criminals
C. show respect
D. prove identity
Answer: