题目内容：
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Train companies in Tokyo are taking action to reduce the number of people jumping in front of trains．They are fitting blue lights on station platforms to try and create a more calming atmosphere．The East Japan Railway Company has invested almost $170,000 to install the lights in all of the 29 stations on the capital's busy Yamanote Line．There has been an alarming rise in the number of people committing suicide at train stations．A total of 68 people threw themselves under trains in the year up to March．This compares with 42 suicides in the same period a year earlier．In 2008, Japan had nearly 2,000 suicides by jumping in front of a train; around six percent of all suicides nationwide．Suicides have risen sharply in the past decade due to poor economic conditions．
No one knows if the blue lights will work．There is no evidence to show that blue light reduces suicidal feelings．Keihan Railway spokesman Osamu Okawa stated: "We thought we had to do something to save lives．We know there is no scientific proof that blue lights deter suicides, but if blue has a soothing effect on the mind, we want to try it to save lives．" The Associated Press news agency reports on a Japanese therapist called Mizuki Takahashi．She explained her reasons why the blue lights might be a good idea: "We associate the color with the sky and the sea．It has a calming effect on agitated people, or people obsessed with one particular thing, which in this case is committing suicide," she said．Other companies are watching this experiment with interest．
Why blue lights are installed in many train stations? A．Because they do not hurt human eyes．
B．Because they are cheaper than regular ones．
C．Because they can help people at night．
D．Because they can reduce the number of suicides．
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