When an emergency situation occurs, observers are more likely to take action if there are few or no other witnesses． This phenomenon is referred to as the bystander effect．
The bystander effect is also called the Genovese effect, which is named after Catherine “Kitty" Genovese, a young woman who was cruelly murdered on March 13, 1964． Early in the morning, 28-year-old Genovese was returning home from work． As she approached her apartment entrance, she was attacked and stabbed （刺） by a man later identified as Winston Moseley． Despite Genovese's repeated cries for help, none of the dozen or so people in the nearby apartment building who heard her cries called police for help． The attack first began at 3:20, but it was not until 3:50 that someone first contacted police．
Many psychologists were set thinking by the incident, as well as most Americans． As the conclusion, the bystander effect came out and later proved by a series of studies and experiments．
There are two major factors that contribute to the bystander effect． First, the presence of other people creates a division of responsibility． Because there are other observers, individuals do not feel as much pressure to take action, since the responsibility to take action is thought to be shared among all of those present． The second reason is the need to behave in correct and socially acceptable ways． When other observers fail to react, individuals often take this as a signal that a response is not needed or not appropriate．
Other researchers have found that onlookers are less likely to take action if the situation is ambiguous． In the case of Kitty Genovese, many of the 38 witnesses reported that they believed that they were witnessing a "lovers' quarrel", and did not realize that the young woman was actually being murdered．
The bystander effect is also called the Genovese effect because          a woman surnamed Genovese．  

A．it somehow caused the murder of

B．its discovery resulted from the murder of

C．it was actually discovered by

D．it always makes people think of

Genovese was murdered         ．  

A．while she was going out	B．in her apartment
C．halfway home	D．near her apartment

Which can NOT have been a possible reason for the neighbors NOT offering Genovese help?

A．They believed in the bystander effect．

B．They thought someone else might help her．

C．They didn't think they should help．

D．They didn't think she needed help．

Before deciding to offer help, observers may         , according to the psychologists． 

A．wait for sort of a signal

B．hesitate and estimate the risk of getting hurt

C．want to be sure it's appropriate to react

D．wonder if the victim is worth helping

The article seems to suggest that, if there had been         observers, Genovese might not have been murdered．   

A．no

B．fewer

C．more

D．braver