Train companies in Tokyo are taking action to reduce the number

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 eye
B、Because they are cheaper than regular one
C、Because they can help people at nigh
D、Because they can reduce the number of suicide
【正确答案】：D
【题目解析】：在文章中明确提到，东京的铁路公司正在采取措施减少在火车前自杀的人数，他们在车站的站台上安装了蓝色的灯来尝试创造一种更加平静的氛围。东日本铁路公司投资了近17万美元在首都繁忙的山手线的所有29个车站安装这些灯。文章还提到了自杀人数的惊人增长，以及过去十年由于经济不景气导致的自杀率急剧上升。 因此，我们可以推断出蓝色灯被安装在许多火车站的原因是它们被认为能够减少自杀的数量。尽管没有明确的科学证据表明蓝色灯可以减少自杀意念，但人们普遍认为蓝色与天空和大海相关联，对激动或执着于某事物（在此情况下为自杀）的人有镇静作用。因此，这些公司决定尝试使用蓝色灯来拯救生命。 所以，正确答案是D，即蓝色灯被安装在许多火车站是因为它们可以减少自杀的数量。