CR - Pickpockets

A year ago, in response to ongoing complaints of pickpocketing at New City’s busy central train station, the city’s police department erected prominent signs throughout the train station warning passengers to beware of pickpockets. As soon as the signs were erected, however, the reported incidence of pickpocketing, per passenger, at the station immediately rose to three times the previous rate—and stayed at the new, higher figure until the signs were removed six months later. As soon as the signs were removed, the per-passenger rate of reported pickpocketing incidents returned to its original level, as quickly as it had risen when the signs were first posted.

Which of the following, if true, does the most to explain the surprising trends in the per-passenger rate of pickpocketing reported at New City’s central train station?

A. In the vast majority of reported incidents of pickpocketing at the station, the victim is traveling during the morning or evening rush, when the station is especially crowded.
B. New City’s police department almost never investigates reports of pickpocketing, nor do insurance policies typically provide any compensation for items stolen in a public place.
C. New City’s train fares, formerly paid with cash in the boarding areas, must now be paid with electronic fare cards sold outside the stations; the signs were posted during the transition period when both means of payment were accepted.
D. A large proportion of passengers, upon reading the signs, would briefly pat down the pockets holding their wallets or other valuables, even if they had to stop walking and put down their baggage to do so.
E. Rising gasoline prices, along with an explosion of new high-density housing within walking distance, have nearly doubled the number of passengers using the station per day since last year.