Bunuel
The downtown area of the city of Stannicton is bustling during the work day, but when all the downtown workers (many of whom live in outlying suburbs) go home, the downtown area, now relatively empty, becomes a haven for crime. Many citizens have reported being attacked in the downtown area in the evening; typically, the assailants do not live downtown but rather come from other neighborhoods. The mayor of Stannicton has charged the city police to reduce the evening downtown crime rate. Police cars patrol the downtown area in the evenings, and the police can monitor any suspicious individual they see, but they can't possibly be on every block at once. In order to extend their "range", the police have established a crime-watch phone number so that downtown residents can report to the police any suspicious looking individual not from the downtown neighborhood, allowing the police to monitor this individual. The police chief feels the establishment of the crime-watch number will play an important part in reducing the evening downtown crime rate.
Which of the following, if true, would provide most support for the prediction that the establishment of the crime-watch number will have its intended effect?
(A) Most of the would-be assailants themselves have mobile phones, and are able to make calls as they move around the downtown neighborhood.
(B) The economic cost of car thefts throughout the city, day and night, is considerably greater than the costs associated with street crimes downtown in the evening.
(C) During the day time, police patrols seldom go downtown, which is bustling with traffic, and instead cruise the other neighborhoods of Stannicton.
(D) Many of the citizens of downtown work during the day and must shop and do laundry at night, so they have a vested interest in seeing the crime rate drop.
(E) While almost all would-be assailants look suspicious and are not from the downtown neighborhood, not everyone who fits that description on the downtown streets in the evening is a would-be assailant.
Official Explanation
Lots of crime in downtown Stannictown at night. More police are patrolling, but they can't be everywhere at one. To solve this problem, police establish a crime-watch phone number, and believe this will genuine help. We are asked: which most convinces us that the crime-watch phone number will help in fighting crime in this situation?
(D) is the credited answer. If the citizens of downtown have a vested interest in the success of the plan, they will use the crime-watch line. Moreover, these citizen are most likely to notice someone who is an outsider, which makes it even more likely that the folks they report are potential criminals.
(A) is irrelevant. Yes, the criminals have cell-phones, but obviously, they will not call the crime-watch number, so whatever calls they do make are irrelevant to the success of this program.
(B) is also irrelevant. Car theft may be a greater concern in the big picture, but this plan is specifically about fighting street-crime downtown at night. We have no idea what other steps the police many be taking to combat auto theft, but clearly it would be something very different that wouldn't have a direct effect on the success of this program.
(C) is also irrelevant. The problem we are addressing is about street crime at night. The prompt already suggests that the problem does not exist in the daytime, so what the police do in the day time is not directly relevant to solving this problem.
(E) is incorrect because it does not provide support for the police chief's plan. In fact, it describes something that may in fact weaken the plan, since the police could overly focus on potential assailants that look suspicious, and not ones that do not look suspicious, but commit assaults.